Chakravarty

Child second language (L2) acquisition and cognitive development: is

earlier always better?

Tushar ChakravartyUniversity of Florida

Department of Spanish and Portuguese Studies 8/10/2012

Abstract (Spanish)

La globalización ha creado un ambiente global donde las comunidades lingüísticas del mundo están cada vez más en contacto. Por eso, en los últimos años, ha habido un aumento en el énfasis en la adquisición de una segunda lengua durante la juventud. Este proyecto se trata de reanalizar el punto de vista común que propone que siempre es “mejor” enseñar una segunda lengua (L2) lo más joven posible durante la niñez. En algunas investigaciones de los últimos años Paradis (e.g. 2010) ha planteado la idea de que los niños con edades inferiores a los seis o siete años no son lo suficiente maduros cognitivamente como para adquirir de manera más eficaz una L2 en un ambiente no natural, como el de un aula. El apoyo a su hipótesis se encontrará en observaciones de un proceso menos rápido y/o eficiente en el caso de niños muy jóvenes en comparación con niños de mayor edad con el mismo tipo y cantidad de exposición y enseñanza. Según Paradis, por no haber alcanzado un estado de cognición maduro, los niños jóvenes no podrían transferir elementos específicos de sintaxis y morfología de su L1 a su L2, específicamente los que se dependen de la maduración cognitiva en general, los cuales pueden ayudar el aparato de la adquisición del lenguaje a filtrar y a procesar el input para formar las pistas sinápticas necesarias. Para investigar esta pregunta, observamos a dos grupos de niños, de edades de 6 a 7 años y de 10 a11 años, quienes han tenido los mismos tipos y duración de exposición al inglés en una clase formal de una escuela bilingüe en Cali, Colombia. Buscamos las diferencias, si existen, entre estos dos grupos de niños para ver si hay una ventaja basada en la edad y madurez para la adquisición inicial de propiedades de la L2 predichas por la hipótesis de Paradis que sean adquiridas con demora. En la primera etapa del proyecto, hemos recogido los datos a través de tres experimentos lingüísticos, que incluyen uno de producción provocada (elicited production), uno de comprensión, y una entrevista personal. En la segunda etapa, hicimos dos experimentos examinando la forma pasiva (tanto la pasiva verbal como la adjetival), comparando las diferencias entre los dos grupos ya mencionados; la pasivo siendo una propiedad tardía al depender de la maduración cognitiva. Los datos de las dos primeras etapas de este estudio indican que, sí, hay una ventaja de mayor edad juvenil para cuestiones de adquisiciones de ciertos aspectos gramaticales.

Abstract (English)

Is there such a thing as “too early” for child L2 acquisition in non-naturalistic contexts?  Highlighting the fact that children below the age of 6-7 are not fully developed cognitively, Paradis (2010) suggests that older children might have an advantage for speed of efficient L2

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development. Until cognition is fully developed children might not be ripe for L2 acquisition, resulting in asymmetric comparative developmental sequences depending on age of exposure. This study compares two sets of child English L2ers in a dual immersion setting in Cali, Colombia, ages 6-7 and 10-11, who have had the same amounts and types of exposure to English. Data collection came from the first stage of this larger research project in which the children (n=25 per group) performed a standardized elicited production picture-story task, a question-answer comprehension task based on the story depicted in the pictures, and an oral interview. This longitudinal study predicts that although the older age group will outperform the younger aged group on the aforementioned tasks that require developed cognitive resources, with sustained and sufficient input both age groups will eventually converge over time. This is an important empirical question beyond child L2 studies because it presents a unique angle to reveal links between linguistic and cognitive development more generally. We begin our discussion with an introduction to the universal properties of child L1A, and the questions that motivate general L2A research.

Empirical questions that prompt child SLA research

The rapid rate of globalization in modern society presents us with a phenomenon

whereby people from all over the world constantly come in contact with one another via trans

global technology, such as travel or the Internet. With all of the resources available to the

developed and developing worlds, many find themselves in a position where they must know

how to communicate with the linguistic community to which they travel or with whom they are

in correspondence. And as more and more people move around the world, there are more

children learning a second language. For these reasons, linguists such as Garuseva, Haznedar,

Paradis, Rothman, Long, Unsworth, among many others, have placed increasing emphasis in

their research programs on the importance of researching child second language acquisition

(L2A). In recent years, examining child L2 acquisition has been expanded beyond the domains

of naturalistic environments only (e.g. through immigration), and has also started to include child

L2 studies in a non-naturalistic, classroom setting that are increasingly more common. This is

done to understand better the process of language learning specifically in the case of young

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children who are not surrounded by the L2 as is the case for naturalistic L2 child acquisition.

This new line of child L2 research joins other fields of linguistic inquiry that have claimed that

effective second language learning could impact society in a beneficial way.

In addition to weighing in on the pedagogical and societal implications of child L2A,

which is beyond the scope and purpose of the present discussion, there are several linguistic and

cognitive theoretical questions that child L2A research aims to address. Linguists believe that

child L2A research has the potential to provide us with great insight into the cognitive

connection between how the brain acts as both a physical organ and as an abstraction of thought

generating consciousness, known as the mind/brain connection, and how it relates to language

acquisition. According to the theory of Universal Grammar (UG) put forward by Chomsky

(1957), due to the similarity amongst the underlying grammatical structures in all of the world’s

languages, the overwhelming conformity of developmental sequencing in child language

acquisition irrespective of the target language, the indeterminacy and degenerate nature of the

input we are exposed to given our resulting grammars and more the ability to acquire and

produce language must be encoded—at some level—in the human genome. Chomsky posits that

all healthy human beings have access to a Language Acquisition Device (LAD) that is activated

in early childhood that streamlines and delimits, if not guarantees, first language acquisition

(L1A). Beyond the debate on the mere existence of LAD (and UG) itself (see e.g. Tomasello

2006), which I put aside for space limitations and scope of this project, there is also some

considerable debate even within linguistic nativism circles as to whether or not LAD/UG is also

available for L2A, especially in adulthood, because many believe that a critical period, known by

the Critical Period Hypothesis (CPH; see Long, 2005; Dekeyser 2000; Birdsong 1999 a&b;

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Rothman 2008 for debate), exists during early childhood that hinders L2A for post-pubescent

adults.

For these reasons and more, child L2A research is a good testing ground for investigating

the role of LAD/UG in L2A in general because it can be used as a vehicle to understand

structures that are problematic for all learners of a language. Child L2A research allows us to

tease out problems related to cognitive immaturity on the one hand, and aged-based limitations

for native-like attainment on the other (see e.g. Schwartz 1992; 2003). Currently, the most

widely accepted belief on the matter of child second language learning is that earlier is always

better for child L2A, whether this be in a naturalistic environment or early teaching in a

classroom setting. This study, aims to reevaluate the validity of the aforementioned “intuitive”,

yet impressionistic proposition by understanding the cognitive and psycholinguistic patterns of

maturation that a child’s mind goes through from birth to puberty and seeing how this comes to

bear on the notion of “early is always better”. Few would deny that early exposure is beneficial,

and indeed research has shown this (see Schwartz, 2003). However, this does not mean that

children in a non-naturalistic setting are ripe at all ages for efficient learning of specific aspects

of language. One goal of this research beyond understanding the cognitive and linguistic

questions it seeks to inform is to see if we can determine which aspects of language are not

acquirable at certain ages so as to create more linguistically informed teaching that maximizes

time and efforts given the limitations of exposure one has in a non-naturalistic setting.

To contextualize the study, we should first understand LAD’s role in acquisition,

developmental sequence in L1A, and the universal properties that govern language in the human

mind. We will also want to understand the role general cognitive development plays in language

acquisition, as both domain specific and domain general properties are assumed to be involved in

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the entirety of the language acquisition process. In fact, the interface between cognition and

language acquisition developments are believed to be key in explaining the route of the path

from an initial state to a steady state of grammatical knowledge. These ideas are explained in

greater detail in the next section.

Patterns of language acquisition and cognitive maturation

Most researchers in the field of linguistics, psychology and medicine maintain that all

healthy children go through essentially the same cognitive developmental sequences pertaining

to language acquisition of their native language (L1) and beyond. This should be

uncontroversial if one understands language development to be linked, at least partially, to the

genetic maturation of the brain itself since different sections of the brain have very specific,

genetically determined, timeframes through which they mature. A wealth of neuroimaging data

support that acquisition of grammar requires the maturation of fiber bundles that connect the

classical language related brain regions, such as Broca’s and Wernicke’s areas of the left

hemisphere, and the dorsal and ventral synaptic pathways (Figure 1) that function both

independently and mutually in language reception and production (see Friederici, 2012 for

review). This language learning mechanism appears to change throughout development as these

brain areas mature at various rates throughout life, but linguists continue to debate whether the

underlying processes involved in acquisition via UG changes throughout an individual’s life (see

Rothman, 2008 for discussion). Both behavioral and imaging data suggest that infants are

equipped with an efficient language-learning device that surpasses the success of the

corresponding adult system since they are able to effectively filter linguistic stimuli in a

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considerably short amount of time in the early stages of life. This is due to the fact that the

infant’s system is more adept at seeking out the stochastic distribution of the morpho-syntactic

and phonological elements in their language input than are post-pubescent adults.

Figure 1 Diffusion Tensor Imaging (DTI) is a magnetic resonance-based anisotropy method that uses the diffusion of water to provide 3D spatial information of myelinated synaptic pathways in the brain (tractography). Myelination refers to a particular type of glial cell that grows on the axon (the portion extending away from the cell body), which functions to increase the propagation of an electrical signal to the synaptic cleft.i The synaptic cleft is the space between two neurons where neurotransmitters are released in order to contact the next neuron in the pathway. These myelinated neurons link certain pathways and regions of the brain that are involved in biological processes, such as language and its acquisition. Major synaptic pathways usually contain millions to billions of myelinted cells linked together. Using post-mortem histochemical techniques, neuroscientists have documented over 10 types of neuronal cells in the brain that differ in their structural identity, which gives rise to the different anatomical regions and particular functions of the central and peripheral nervous systems that encompass the organ itself and its activity.ii The regions in the brain involved in language processing are many, but the main ones include the Broca’s area, Wernicke’s area, cerebral cortex (prefrontal cortex, in particular), hippocampus and the temporal lobe. iii All of these regions synergistically orchestrate the symphony of language. Here we see a DTI image from Friederici, 2012 of the fiber tracts in 7-year-old children and adult brains. The ventral pathway (pink) in 7-year-old children resembles that of the adults’, but the dorsal pathway (purple) is markedly different, which suggests that certain areas of cognition, and perhaps language acquisition mechanisms, such as working memory, differ markedly, whereas other pathways may not necessarily. This maturation-dependent anatomical difference may affect the manner in which children acquire their L1, L2, Ln until full cognitive development later in life

Language learning begins prior to birth when the infant is still in the amniotic cavity of

the mother’s womb. At this stage of life, the prenatal brain can perceive the sounds and prosody

of the mother’s voice, and the timing of phonemes even though there is a considerable amount of

uterine muffling (e.g. Smith et al., 2003). Language learning continues throughout the first few

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weeks, months and years after birth, while infants start to babble and listen for language input,

which is known as step 1 of acquisition. Crain and Lillo-Martin (1991: pp) state that, “2-week-

old babies [can] discriminate between a so-called voiced consonant such as ‘ba,’ where the vocal

cords begin to vibrate early on, as compared to an unvoiced consonant such as ‘pa,’ where the

vocal cords begin to vibrate only at the vowel, lal (ahh)”, when spoken to. Stage 1 constitutes

ages 1-6 months, in which the statistical learning of sounds is primarily based on the

dependencies of auditory speech input (see Friederici 2012). After a year of babbling according

to the sound and intonation contour of their adult native language and several stages of

vocabulary building throughout the second year, two-year-old children enter stage 2 at which

point they have learned the general syntactic structures such as word order (SVO, for English)

depending on the particular language, and they being to process the syntactic phrase structures of

clauses and subordinate clauses. Stage 3 encompasses ages 3-7, when children can comprehend

and produce complex syntactic structures that include noun phrases as well as embedded

structures. At this point, their mean length of utterances (MLU), which is the understood

grammatical proficiency level determined by the length of the sentences that they produce in oral

communication, will continue to increase for the rest of their child years until a little before

puberty. This outline of L1 acquisition helps guide the questions that must be asked in order to

map out the rest of L1A, and in our case, to understand how L2A will be constrained by

interference and transfer of certain L1 grammatical properties as children mature cognitively.

However, much research has shown that language development is not entirely

independent of general cognitive development. For example, some predictable properties

emerge later in child language, comprehension and production, that do not correspond to

linguistic complexity or relative frequency in available input themself. In other words, some

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properties that are strictly speaking less formally complex than others happen to emerge later in

child language. This alone suggests that linguistic complexity and/or frequency alone are not the

only driving forces of grammatical development. Some properties are believed to emerge later

due to their dependence on domains of cognition that are themselves in the process of

maturation. For example, we know that Theory of Mind (TofM)--essentially the cognitive state

of assigning false beliefs and understanding the complexity of “common groundedness”—

develops in later childhood. De Villiers (2007) presents a meta-analysis of the many studies on

the relationship between TofM development and its linguistic corollaries, showing that linguistic

properties that require a false belief system and/or the ability to take other points of view than

only that of the speaker emerge later as well, in fact, in tandem with non-linguistic tests probing

for TofM development. This is of particular importance for the present study since if children do

not have TofM and other cognitive domains fully mature at the age of 4 and 5 where in some

cases child L2 acquisition starts in the classroom setting this will have inevitable consequences

for what they are able to acquire at this age, not only in the L1 but also in the L2.

Background for the study

According to the Maturation Hypothesis (MH), proposed by Borer and Wexler (1987), the

fact that neural fiber tracts that are involved in the working memory system develop later in

childhood has observable impacts in language development. Essentially, and simplifying a bit,

the MH predicts that grammatical properties that depend on developing neurological and

cognitive systems will be slower in acquisition than other properties that are truly encapsulated

by linguistic modularity. The passive construction is a prime candidate for such a property that

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would develop later due to its connection to the developing memory systems because it involves

the tracking of A-chains or the chain of traces within the linguistic derivation after covert

movement has taken place. Passives are said to involve A-chains under the proposal that they

start in their deep-structure as active sentences that undergo transformations from the active form

to their passive output production. In other words, a sentence like Mary was kissed by John

starts as John kisses Mary, where the subject is the agent and the object is the experiencer.

However, through a set of transformations during the course of linguistic processing from the

semantic form to the syntactic surface production the thematic roles of agentivity and

experiencer are inverted syntactically but not semantically. This process is understood to tax the

memory systems and therefore, given the MH, this should be delayed and/or variable in children

until their memory systems are fully developed. Support for this approach is provided in

numerous behavioral and observational studies that children have trouble assigning the

agent/patient (experiencer) relationship mediated through the by phrase in these syntactic

structures and the fact that children have limited working memory to assist them in this process

(e.g. Wexler, 1990; Pierce, 1992, among others, but see Fox and Grodzinsky, 1998).

One of the goals of this study is to test the latent predications that the MH has for child L2,

namely that children of a very young age are not ripe for L2 acquisition of certain structures,

passives for example, in any language they are exposed to, meaning if these problems are

inevitable for the development of their L1, they might even be more pronounced for L2

acquisition at young ages where input is highly restricted and decontextualized. Another goal of

this study is to demonstrate that the Critical Period Hypothesis makes no tangible predictions for

child L2A, contrary to divergent suggestions made by some such as Long (2005). To test

Paradis’ claim that “early is not always better” when we consider the acquisition of particular

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domains of grammar, we employ various linguistic experiments in the methodology. These

experiments test the connection of maturational cognitive constraints on language development

at particular ages via an examination of a property predicted to be unacquirable for the young

children of the study, yet not for the older children participants even when they have the same

exposure since age is highlighted as the deterministic factor.

Methodology

To test the proposal that “earlier is not always better” for specific domains we are in the

process of undertaking a longitudinal study testing age factors related to cognitive development

(memory systems) between two age groups of children from Cali, Colombia, who are learning

English as a second language (EL2) in a dual-immersion non-naturalistic, classroom setting. This

longitudinal study will span 5 years and is tracking a 1st grade group and a 4th grade group at the

time of initial testing two years ago who both had had three years of initial language instruction

in English (i.e. the 1st graders started L2A at age 3-4 and are now 6-7 at the time of testing, and

the 4th graders started at age 6-7 and are now 9-10). Recall that Paradis (2010) suggests that

younger children (before the age of 7) are less efficient for second language acquisition for

interrelated reasons. She claims that their L1 before the age of 6-7 is not fully developed and,

therefore, transfer is destined to be incomplete, that their memory systems are immature until the

age of 7 and that other domains of cognition relevant to language are also immature. This should

have deterministic effects to what children can be expected to uptake in L2 acquisition

irrespective of the type and even amount of exposure they have. Simply put, children above the

age of 7 are riper to uptake the full gamut of linguistic properties modeled in the input they hear,

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and this should be detectable by testing different groups as we are doing. In other words, until

cognition related to hippocampal based working memory, the cerebral cortex, and other sections

of the brain related to language reception and production are fully developed, younger children

are not as able to acquire certain properties of the L2. Also, a lack of developed cognition at a

time prior to full L1 acquisition renders the L2 child as having less cognitive resources available

for L2 acquisition since much of cognition at this age is occupied already in the task of L1

convergence (Paradis, 2010). This could mean that there is an even greater delay in child L2A

for certain properties than what one sees in normal L1 development of these same so-called

delayed properties, an aspect that our research will also seek to document if possible. This type

of research is important for bridging the gap between the differences and similarities amongst

child and adult L2A; what subsections of LAD are similar and distinct, if any, when comparing

adults and children learning an L2? In most research articles, LAD is an abstract concept, but

here we endeavor to understand it as a more concrete model. Information gathered from this

project may provide deep insight regarding LAD’s architecture and its relationship to systems

outside the linguistic module.

Subject Selection

We have recently finished two phases out of a three-phased project, which is aimed at

testing Paradis’ predictions and providing behavioral data to test the MH in a unique population,

namely, child L2A (Borer and Wexler, 1987). The three phases of this project were conducted at

the Colegio Berchman’s, a dual immersion setting in Cali, Colombia, upon the aforementioned

younger and older groups of children. Berchman was selected due to the relative homogeneity of

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its students. Since Berchman is a private institution that requires a substantial enrollment fee all

of the students come from an upper middle socio-economic, Colombian background. Using

Berchman also controlled for the linguistic environment that the children would be exposed to. A

recent review article by Rothman and Guijarro-Fuentes (2010) points out the “possible

differences in the grammatical quality of the input classroom learners receive relative to

naturalistic learners (L1 and L2 alike).” So as to minimize differences in the input, these students

were selected on the basis that they had similar Spanish and English input both inside and

outside of the classroom. All of the students were raised in a Spanish-speaking, predominantly

monolingual household, with minimal access to English outside of the classroom, aside from the

products of globalization (i.e. the radio, internet, television, etc.) and distant relatives who live in

the United States—as many wealthy Colombian families do. Thus, all of the students had similar

amounts of exposure to English. Now to account for the obvious difference in amount of

exposure by age, selecting Berchman was also ideal. It happened to be the case that three years

prior to the onset of the study the school had transitioned to a dual-immersion school. This

means that despite the three years in chronological age that separated the older and younger

groups, they each had 3 years of similar exposure type with the same style and general

methodology. To the extent possible, the only difference between these two child L2 groups was

the age of onset of first initial significant exposure to English. Thus, selection of this school

allows us to assume that all of the students have similar input, but differ in the one crucial

variable needed to test the hypotheses under investigation, with all other factors held

approximately equal.

There were several control groups that were included in this study in order to allow for a

holistic evaluation of the results obtained from the two child groups: a Spanish-native speaking

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adult group that learned English as an L2 (SL1/EL2 Adults), and an English-native speaking

adult control group that learned Spanish as an L2 (EL1/SL2). In addition to these adult control

groups, another student member of the larger lab project conducted a study that mimicked all of

the parameters of this study, except that studied English native child L2 learners in a dual-

immersion Spanish as a second language program in Florida (Rietbergen 2011).

Procedure

Phase 1: In the first phase, all of the children underwent three types of elicited production tasks

that one of their English teachers conducted with them individually: an oral personal interview, a

standardized story telling task, and follow up question-comprehension elicited production task

based on the story telling task (the tasks are standardized, and normed to be language

independent used as part of the University of Edmonton child L2A project directed by Professor

Johanne Paradis). The story telling task involves a series of pictures (Figure 2) that, as according

to one L2A research group, do not, “disfavor either the child subjects or the adult subjects…

[since] all the actions depicted in the pictures [are] considered general enough” (Unsworth,

2008). Adults are also considered for this elicited production experiment in order to include

possible adult L2er controls in future studies. We then transcribed all of the elicited production

child-output data in order to calculate a relative elicited MLUw. We examined the transcriptions

for error frequency and type, as well as syntactic structure in both of the child groups.

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Figure 2: Pictures used in the story telling task in experiment 1 of phase 1

Phase 2: The second phase of the project tested specific linguistic domains that are more dependent on

linguistic external cognition and/or linguistic maturation that should be slower to develop with the

same types of exposure across child L2ers of different ages at onset based on the reasons enumerated

above. The property tested was the passive voice syntactic construction. Research has shown that L1

English-speaking children fully develop the passive voice after the age of 4 and not fully until about

age 9 (Levin 2011). A Spanish L1 child will follow the same pattern as English L1 learners, but since

Spanish has two competing forms of the passive tense, Spanish L1 children learning English as an L2

might be predicted to have greater difficulty acquiring this tense. One note that must be pointed out

concerning the following tasks is that the children in this study were not explicitly taught the passive

construction in their English classes prior to testing, so acquisition of this structure is entirely

dependent on true acquisition that utilizes the neural mechanisms from their L1 to understand new

information presented to them implicitly.

Experiment 1 Picture Identification Task:

We predict that child L1 speakers of Spanish that are learning English as a second

language from the age of four, tested now at the age group between six and seven, will have

difficulty understanding the passive construction (particularly verbal passives as opposed to

adjectival passives) in the English language due to general cognitive maturation (which should

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effect A-chain computation). If Paradis’ contention is on the right track, then we expect the

younger group to perform differently on these tasks as compared to the older group of L2

children who, being older at the time of first exposure and thus having a more developed

memory system and being otherwise more cognitively mature should have been in a better

position to acquire passives. Thus, despite the fact that each of the groups have received the

same amount of exposure over the same time period, the predictions based on the hypotheses

being tested would expect the older children to outperform the younger children significantly.

The first experiment described for phase 2 uses the Picture Identification Task derived

from Hendricks and Wiley (1998) in order to determine whether the child learner could

accurately select the correct version of the passive construction that describes the events in an

image that we presented to them. The picture identification task used in this project utilized

novel pictures that depicted characters from the children’s television show, Spongebob

Squarepants, which has a global audience. After a general session of training to familiarize them

with the procedure and acclimate them to the puppets used to solicit their responses, the pictures

were displayed on a 15-inch MacBook Air in a PowerPoint presentation. Each child sat at a table

with the researchers and was initially acquainted with the Sesame Street hand puppets, Elmo,

Grover and Emma, whose sole purpose was to make the testing environment less stressful for the

children, thus enabling them to answer each test item to the best of their abilities. The puppets

would then introduce the Spongebob characters (Figure 3) in an introductory slide, by asking

them if they knew what the characters’ Spanish names were. The children were then

subsequently taught the English-equivalent names for each of the characters that would be used

in the test item scenarios, and once they demonstrated that they knew the names of the characters

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by verbally repeating them on their own to the experimenters, they were deemed ready to begin

the test.

Figure 3: Character introduction slide

The experimenters tested knowledge of passives via asking for interpretations of target

sentences uttered to them by the puppets after which they were presented with two competing

pictures that depicted either an active or a passive interpretation. That is, each picture depicted

one of two characters either receiving or delivering the action of the sentence in either the active

or the passive construction (Figure 4). The active construction was meant to act as a

counterbalance for the target passive sentences, and indeed half of the target sentences were

actives to make sure they understood active constructions as well. Both scenarios were

randomized for each participant so as to evenly distribute the 12 target passives and 12

counterbalanced active sentences, giving a total of 24 different verb actions. Below is an

example of one set of pictures.

Active:

Mr. Krabs touched Squidward (N=4 OF THIS TYPE)

Squidward touched Mr. Krabs (N=4 OF THIS TYPE)

Long passive:

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Squidward was touched by Mr. Krabs (N=4 OF THIS TYPE)

Mr. Krabs was touched by Squidward (N=4 OF THIS TYPE)

Figure 4: One scenario used in Experiment 1 of Phase 2

Experiment 2 Differentiating Lexical Adjectival Passives and True Verbal Passives:

In this experiment, we tested the child’s ability to differentiate between lexical adjectival

passives and true verbal passives in a similar fashion to the experiment described above. It has

been suggested that the lack of by-phrases in the passive constructions children hear may hinder

their assignment of correct thematic roles (agent, patient) (Fox & Grodzinky, 1998), rendering

the passive harder to process, comprehend, and produce. So, looking at adjectival passives is

useful under this scenario since they do not have by-phrases and are thus predictively easier.

The idea is that children might reanalyze true verbal passives as adjectival passives given rise to

apparent variability in production and comprehension since sometimes an adjectival passive in a

verbal passive context takes a similar form and thus cannot be differentiated. Our goal was then

to see if children would fare better on adjectival passives. We still predict that the younger age

group will have difficulty understanding the passive construction presented in each scenario

listed below, especially so when it is a true verbal passive. Support for this proposal was drawn

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from the observation that English L1 learners younger than age 7 rarely use a by-phrase, the

hallmark of a true verbal passive, resulting in surface productions that look like the lexical

adjectival passive construction (Horgan, 1978). We therefore have developed the following two

scenarios to test both our English L2 learner groups’ ability to distinguish between the two

passive constructions listed below in scenarios A and B.

Scenario A depicts an example of the lexical adjectival passive since it lacks the by-

phrase. Scenario B depicts a semantically non-reversible sentence, where the agent and patient

are not interchangeable due to the real-life implausibility of the event. Thus it cannot be

reanalyzed logically as an adjectival passive. There were six situations in total, and each set

consisted of the two scenarios per one slide in the same aforementioned power-point presentation

format. Each child was presented with an image that introduces the character in each set.

Admittedly, this task is more demanding since it presents a context that the child needs to keep in

working memory when considering the context cues. This might have favored better

performance by the older children, but this is one of the very points of the MH itself which

claims that a source of difficulty for acquisition of these structures is at least partially related to

maturation constraints on the memory systems’ maturation. The experimenters then dictated

scenario A, posed the question, and then showed the two pictures that describe each scenario for

the set. The child then chose which picture best described the sentence for scenario A. The same

process occurred for scenario B, and the rest of the 5 sets. Below is an example of one set of

pictures.

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Scenario A:

Mr. Krabs owns a restaurant. He doesn’t like the color of the walls, so he plans to paint them a

different color, probably red. Which picture best describes this sentence?

The walls were painted brown.

Scenario B:

Mr. Krabs owns a restaurant. He wanted to change the brown color of his walls. So, Mr. Krabs

decides to paint the walls red. Which picture best describes this sentence?

The walls are painted red by Mr. Krabs.

Figure 5: One scenario used in Experiment 2 of Phase 2

Phase 3: Assuming the results of Phase 2 bear out, as we will see they do, the next phase of the

project (already done this past May by other researchers on the larger project) is to do a

repetition of these same tasks one year later and then every two years thereafter for a total of 6

years. The logic of the continuation of the study rests in the assumption that all children have

access to whatever internal mechanisms (domain-general and/or domain-specific) are used to

acquire one’s L1. Thus, with sustained, quality input any differences noted across the younger

and older child groups should only be developmental, so the younger children should catch up

eventually. We predict to find that the younger children will catch up to the older children,

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perhaps by the second time of testing. At least some children from each group are predicted to

show very good levels of acquisition as time advances.

Results

Phase 1 Results:

Once the elicited production tasks were transcribed and then analyzed, we calculated

MLUw’s for each of the tasks. Figure 5b shows that the child L2 group who was 7-8 from the

onset of first exposure (the older group) is, by some measures, much more advanced after 3 years

as a group (using MLU measures, discursive stylistics in story telling, and overall fluency) as

compared to the younger group.  However, upon analyzing each group’s raw data, the types of

errors in both groups’ productions shared commonalities such as errors in verbal agreement, an

over use of articles, errors in lexical choice, dropping of subject pronouns in obligatory contexts

to name just a few. 

a)

b)Figure 5: MLUw for each of the elicited production tasks. a) 1st grade MLUw b) 4th grade MLUw

The results show that the younger 1st grade group did, in fact, have a lower MLU count in

English when compared to the 4th grade group, holistically and in each of the three production

tasks individually. This finding supports Paradis’ hypothesis and also follows the predicted

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outline for the age-related developmental pattern of child psycholinguistics that was previously

mentioned in the introduction. Here, we can see that the average MLU across all three tasks is

quite high, perhaps higher than expected. This is not surprising, however, since two of the tasks

are elicited production with detailed pictures, providing the children with ample visual context to

create a story. However, it must be noted that the MLUs for both groups are much lower than

the combined MLUs for the only truly spontaneous production task, the oral interviews. This

task is probably the true indicator of their overall proficiency, to the extent that MLU is a viable

measure for proficiency. We must also note that the MLU of the 1st grader child L2ers is

significantly lower than the 4th for this category as was expected.

Phase 2 Results:

Similar to the results from Phase 1, the experiments from Phase 2 show that the older

children were better able to comprehend the passive construction. Figures 6 and 7 show that the

EL1/SL2 adult control group performed at ceiling level for both syntactic constructions (100%

correct for the active tense and 98% correct for the passive tense), and that the SL1/EL2 adult

control group followed closely behind, but still underperformed in comparison to the native

English group, which was statistically significant (see Figure 8). Both the 1st and 4th grade

groups performed better on the active construction, but the 4th grade group outperformed the 1st

grade group on both the active and the passive constructions. In addition, the 4th grade group and

the SL1/EL2 performed similarly on the active construction, but still worse than both the

SL1/EL2 and EL1/SL2 adult control groups, which was expected since they had developed

(cognitively and linguistically in the L1) further at the onset of acquisition (Demuth, 2010). This

supports Paradis’ prediction because the older age group was on target with passives in their L1

at the time of first exposure to English whereas this is not the case for the younger children.

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Figure 6: Numerical values for all of the groups involved in Experiment 1 of Phase 2. Y-axis contains the percent correct (out of 100%); X-axis contains group types involved in this experiment.

Figure 7: Here we display the results from Figure 5, but as a graphical analysis, with the estimated marginal means on the Y-axis. The X-axis contains the type of experiment: type 1 = experiment 1, type 2 = experiment 2. Group types are labeled in different colors in the box to the right of the graph.

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Figure 8: Statistical analysis for experiments 1 and 2. The p-value is less than 0.001.

Discussion

The data obtained from the experiments during both phases 1 and 2 indicate that a

maturational advantage does exist when it comes to child L2A for specific grammatical

properties, such as the passive construction. The results from phases 1 and 2 suggest that the

younger age children are at a lower level of relevant cognitive development, echoed in tangible

differences along the predicted lines for specific domains of linguistic production in their L2.

However, what is shown here for their L2 should also be noticeable in the L1, even if in a less

polarized way, since issues traceable to the development of cognition should not be unique to an

L2. A proper analysis that should be conducted in subsequent studies in order to control for

language production abilities and general cognitive developmental effects in both the age groups

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is an elicited production experiment, akin to what was done in phase 2, in their native language,

Spanish, to test the assertion that what is at play here is in fact a consequence of general

cognitive development and not a byproduct of something specific to L2 acquisition and age in

children. Nonetheless, the aggregate data for each group are consistent with the claim that the

younger children are less developed in this regard for L2 language production after 3 years of

instruction, as compared to the older group. The results from the passives experiments concord

nicely with phase 1 data, also suggesting that the younger children are less adept at

understanding the L2 passive construction after three years of exposure. Taken together, the

whole of the data supports Paradis’ predictions and could in fact be taken as indirect evidence

that the older child group has a more developed memory system than the younger group.

Imaging data in favor of the Maturation Hypothesis: future directions

The results from this study constitute behavioral data that are consistent with the MH for

child L2A, but recent imaging data (i.e. Friederici, 2012) has also detected maturational

limitations in differently aged children as well, which sheds some light upon the anatomical

underpinnings involved in grammatical development and its connection to cognitive maturation

within the brain. Adult fMRI studies from Friederici (2012) suggest that “the ability to build

syntactic phrases might be subserved by a network involving the inferior frontal gyrus and the

temporal cortex that is connected by a ventrally located pathway, which supports local phrase

structure building and comprehension of simple [word order (SVO in English)] sentences”. In

addition to this, Friederici has found that both adults and 2 and a half year old children display a

biphasic ELAN/P600 effect in response to the processing of phrase structure violations, whereas

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2 year olds only display a P600. These data suggest that the fast initial structure building

processes are not yet fully established by the age of 2, but develop literally months later. While

this does not bear much significance on child L2A at the ages studied herein, recall the youngest

children were 4 at L2 onset, it does suggest that certain developmental constraints do exist quite

physically. So going back to our findings, an anatomical explanation, possibly in the form of

electrophysiological data, would be an appropriate next step in showing the cognitive differences

between the two age groups performing similar tasks in a future child L2A study that probes the

MH, and its contentions.

In addition, Friderici (2012) finds that, “Processing of morphosyntactic violations show a

LAN/P600 in adults, whereas 3-year-old children only display a P600”. Due to these and other

electrophysiological data Friederici and others admit that they are not sure whether, “children

around the age of 3 and 4 utilize the same brain regions as adults”. An interesting follow up

study would be to find an exact age at which children/post-pubescent individuals begin to show

the LAN/P600, and whether this would also show up in L2A at these ages, because its presence

in a maturational pattern could be supportive of the idea that the cognitive development delimits

certain L1/L2 grammatical properties. Finally, in addition to the aforementioned data, the

superior temporal gyrus and superior temporal lobe, which have been shown to be involved in

the processing of complex syntactic structures, does not fully develop until later in child

maturation: around the ages of 7 and 8 (Friederici, 2012). As such, it could be hypothesized that

these areas are involved in the comprehension of the passive construction, or other so-called late

acquired properties, thus sidestepping the issue of whether UG itself matures or not (the so-

called maturation versus weak/strong continuity debate, see Guasti, 2002), since they also

constitute part of the areas that are involved in the working memory systems during language

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processing and production. Unfortunately these types of experiments are difficult to administer

considering the large number of participants, their potential ages, the permission to scan

children’s brains from the IRB, and current lack of funding.

Conclusion

The data obtained from the present study suggest that children may be limited cognitively

from acquiring some parts of the second language in a non-naturalistic setting, until a particular

age, due to certain psycholinguistic, general cognitive and even some L1 constraints since their

brains are still in the process of developing, which means that key areas related to language

acquisition, an L1 or L2 alike, are not fully mature/usable. Children are also in the process of

forming useful synapses related to their L1—a more pressing matter for an immature and

encumbered brain—which they will utilize and retain throughout their lives. The contentiously

debated topic of whether or not there is a critical period for language acquisition is seemingly not

relevant to cases of child L2A since by all accounts children at such young ages would not have

surpassed the proverbial window of opportunity to be ripe for linguistic learning. However, it

does bring indirect evidence to bear on the notion of the CPH. By showing that children too

have similar difficulties to adults and even some unique ones in their development of L2A tells

us that being a child alone is not sufficient to guarantee effortless and/or seemingly

uncomplicated acquisition. Like adults, child L2 learners have various degrees of influence from

their L1 or transfer effects. Unlike adults and somewhat like child L1 learners, they are limited

cognitively in terms of how they can handle the input to which they are exposed. When coupled

with qualitative and quantitative difference in the input they received as compared to child L1

learners, especially in non-naturalistic settings such as dual-immersion classrooms. What we see

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is a process that is unique, even is reflecting some similarities to adult L2A and child L1A.

Looking towards the continuation of this study in subsequent phases, we predict that the younger

children should catch up to the older children, perhaps by the second time of testing since they

will eventually mature cognitively. If these predictions are sustained by empirical evidence, then

perhaps earlier is not always better for child second language acquisition in certain domains.

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