Background

Infants and toddlers have detailed representations for their known vocabulary items

Consonants (e.g., Swingley & Aslin, 2000; Fennel & Werker, 2003; Halle & de Boysson-Bardie, 1996)

Vowels (e.g., Mani & Plunkett, 2007)

No study has examined the nature of representations of lexical tones during early vocabulary development

Lexical tone contrasts are perceived by tone-learning infants at the preverbal stage (e.g., Gao, Shi, & Li, 2010; Mattock & Burnham 2006; Tsao, 2008)

Lexical tones in Mandarin & Tone 2 – Tone 3 neutralization

Four tones (See Fig. 1): Tone 1 (high level) Tone 2 (high rising)Tone 3 (low dipping)Tone 4 (high falling)

Fig. 1 Time-normalized and pitch-normalized F0 contours of the four lexical tones in Mandarin, produced by a female native speaker. (data from Lee Sung Hoon, Graduate School, Chinese Academy of Social Sciences)

Tone2-Tone3 sandhi rule: Tone3-Tone2 in the environment of a following Tone 3

i.e., Tone 3 Tone 3 → Tone 2 Tone 3.

e.g., xiao3 (“small”) + gou3 (“dog”) → Tone 2 Tone 3

Research questions

Phonological Neutralization and the Representation of Lexical Tones in Mandarin-speaking Toddlers

Jun Gao 1, Rushen Shi 2, Aijun Li 3

gaojungscass@126.com, shi.rushen@uqam.ca, liaj@cass.org.cn

Experiment 1

Hypotheses If toddlers lack the full knowledge of the Tone 2-Tone 3 sandhi rule, the two phonemic tones may be represented as free variations (i.e., non-distinguishable) in the lexicon;

If toddlers have acquired the Tone 2-Tone 3 sandhi rule (i.e., knowing that Tone 2 and Tone 3 are phonemic and are only neutralized in specific context), they should have distinctive representations for the two tones.

MethodsParticipants: 16 Mandarin - learning toddlers; 19-29 months oldSpeech stimuliFour monosyllabic key familiar words, two in Tone 2 and two in Tone 3Tone 2 (rising tone): yang2 (“sheep”), chuang2 (“bed”)Tone 3 (low dipping tone): ma3 (“horse”), wan3 (“bowl”)The Tone 2 and Tone 3 targets were in a non-neutralizable context in this studyProcedureIntermodal preferential looking procedure (See Fig. 2)Two side-by-side pictures of familiar words per trial (6.5 secs); 24 trials

Two test trial types: Correct pronunciation (CP):

yang2, chuang2, ma3, wan3Mispronunciation (MP):

yang2 mispronounced as yang3

chuang2 mispronounced as chuang3

ma3 mispronounced as ma2wan3 mispronounced as wan2

Results

Measure: proportion of looking to the targettarget looking time divided by the sum of target looking time and distractor looking time

Analysis window: starting 375msec from the onset of the first production of the target, to 2 sec (See Fig. 3)

Fig. 3 The structure of a trial

Fig. 4 Proportion of looking time to target in CP vs. MP trials

Comparison to chance level (0.5): children recognized the target words in CP and MP

CP significantly above chance, p = 0.000, 2-tailed

MP significantly above chance, p = 0.001, 2-tailed

CP vs. MP comparison: mispronunciation of tones did not impede target recognition CP & MP not different, p = 0.751, 2-tailed

Toddlers did not distinguish Tone 2 vs. Tone 3 in familiar words, possibly due to Tone 2 – Tone 3 sandhi operations in the input; infants lack full knowledge of this sandhi rule.

MethodsParticipants: 18 Mandarin - learning toddlers; 19-29 months old

Speech stimuliThe monosyllabic key familiar words of Experiment 1:

Tone2 (rising tone): yang2 (“sheep”), chuang2 (“bed”)Tone3(low dipping tone): ma3 (“horse”), wan3 (“bowl”)

Procedure Intermodal preferential looking procedure Two side-by-side pictures of familiar words per trial (6.5 secs); 24 trials

Two test trial types: Correct pronunciation (CP):

yang2, chuang2, ma3, wan3 Mispronunciation (MP):

yang2 mispronounced as yang4chuang2 mispronounced as chuang4ma3 mispronounced as ma4wan3 mispronounced as wan4

(Note: Tone 2 & Tone 3 are never neutralized with Tone 4 in any context)

Results

Fig. 5 Proportion of looking time to target in CP vs. MP trials

Comparison to chance level (0.5): children recognized the target words in CP and MP

CP significantly above chance, p = 0.005, 2-tailed

MP significantly above chance, p = 0.06, 2-tailed

CP vs. MP comparison: mispronunciation of tones did not impede target recognition

CP & MP not different, p = 0.687, 2-tailed

Toddlers did not distinguish Tone 2 vs. Tone 4, nor Tone 3 vs. Tone 4 in familiar words.

Fig. 2 One example of the pictures presented to the subjects

General Discussion

Experiment 1 & 2 taken together, toddlers showed

No distinctive lexical representations for Tone 2 versus Tone 3 (neutralizable in one specific context);

No distinctive lexical representations for Tone 2 versus Tone 4 (non-neutralizale contrast);

No distinctive lexical representations for Tone 3 versus Tone 4 (non-neutralizale contrast)

Preverbal tone-learning infants can perceive lexical contrasts in Mandarin and Thai (Gao, Shi, & Li, 2010; Mattock & Burnham, 2006; Tsao, 2008).

Possible explanation for the non-discrimination of tonal contrasts: The present task not sensitive enough: familiar-familiar pairings

Subsequent experiment: A more sensitive task: familiar – unfamiliar pairings (White & Morgan, 2008); preliminary results show an MP effect for tonal contrasts that are never subject to neutralization (Tone 2 vs. Tone 4; Tone 3 vs. Tone 4).

References

Fennell, C. T., & Werker, J. F. (2003). Early word learners' ability to access phonetic detail in well-known words. Language and Speech, 46(2-3), 245.

Gao, J., Shi, R., & Li, A. (2010). Categorization of lexical tones in Mandarin-learning infants. Paper presented at the the Fifth International Conference on Speech Prosody, 2010, Chicago.

Hallé, P. A., & de Boysson-Bardies, B. (1996). The format of representation of recognized words in infants' early receptive lexicon. Infant behavior and development, 19(4), 463-481.

Mani, N., & Plunkett, K. (2007). Phonological specificity of vowels and consonants in early lexical representations. Journal of Memory and Language, 57(2), 252-272.

Mattock, K., & Burnham, D. (2006). Chinese and English infants' tone perception: Evidence for perceptual reorganization. Infancy, 10(3), 241-265.

Swingley, D., & Aslin, R. N. (2000). Spoken word recognition and lexical representation in very young children. Cognition, 76(2), 147-166.

Tsao, F.-M. (2008). The Effect of Acoustical Similarity on Lexical-Tone Perception of One-Year-Old Mandarin-Learning Infants. Chinese Journal of Psychology, 50(2), 111-124.

White, K. S., & Morgan, J. L. (2008). Sub-segmental detail in early lexical representations. Journal of Memory and Language, 59(1), 114-132.

AcknowledgementThis work was supported by the CASS Key project fund and the Chinese Social Science Fund to the third author and the first author, and grants from NSERC, SSHRC and CFI to the second author.

Affiliations 1.3. Institute of Linguistics, Chinese Academy of Social Sciences, China2. Université du Québec à Montréal, Canada

Experiment 2

Do toddlers distinctively represent tonal contrasts that are not subject to neutralization?

Do toddlers distinctively represent tonal contrasts that are not subject to neutralization?

Do lexical-tone-learning toddlerspossess distinctive tonal representations for familiar words?

Does tonal neutralization affect toddler’s tonal representations of familiar words?

Do lexical-tone-learning toddlerspossess distinctive tonal representations for familiar words?

Does tonal neutralization affect toddler’s tonal representations of familiar words?