Finding your way through the woods with GrETEL
Liesbeth AugustinusVincent Vandeghinste
Ineke SchuurmanFrank Van Eynde
TABU-dag - June 14, 2013
GrETEL• Greedy Extraction of Trees for Empirical Linguistics
• Query engine for treebanks
• Nederbooms projectExploitation of Dutch treebanksfor research in linguistics
GrETEL• Greedy Extraction of Trees for Empirical Linguistics
• Query engine for treebanks
• Nederbooms projectExploitation of Dutch treebanksfor research in linguistics
• Goalso User-friendly toolso Access to large data fileso Fast and accurate
GrETEL• Greedy Extraction of Trees for Empirical Linguistics
• Query engine for treebanks
• Treebank = syntactically annotated corpuse.g. Penn Treebank (English), TüBa (German),LASSY, CGN (Dutch)
TREEBANKS
CGN core corpus LASSY smallSpoken Dutch Written Dutch
Stylistic & regional differences
conversations vs read textsNL vs VL
Stylistic differences
Wikipedia vs legal texts
± 1M tokens ± 1M tokens
130k sentences 65k sentences
Manually corrected Manually corrected
GrETEL• Greedy Extraction of Trees for Empirical Linguistics
• Query engine for treebanks
• Treebank = syntactically annotated corpuse.g. Penn Treebank (English), TüBa (German),LASSY, CGN (Dutch)
• Parsere.g. Alpino (Van Noord 2006)
ALPINO PARSER
Dit is een zin. >> ALPINO parser >>“This is a sentence.”
ALPINO PARSER
Dit is een zin. >> ALPINO parser >>“This is a sentence.”
XML treesQuery language: XPath
XPATH
//node[@cat="smain" and node[@rel="su" and @pt="vnw" and @lemma="dit"] and node[@rel="hd" and @pt="ww" and @lemma="zijn"] and node[@rel="predc" and @cat="np" and node[@rel="det" and @pt="lid" and @lemma="een"] and node[@rel="hd" and @pt="n" and @lemma="zin"]]]
XPATH
//node[@cat="smain" and node[@rel="su" and @pt="vnw" and @lemma="dit"] and node[@rel="hd" and @pt="ww" and @lemma="zijn"] and node[@rel="predc" and @cat="np" and node[@rel="det" and @pt="lid" and @lemma="een"] and node[@rel="hd" and @pt="n" and @lemma="zin"]]]
XPATH
//node[@cat="smain" and node[@rel="su" and @pt="vnw" and @lemma="dit"] and node[@rel="hd" and @pt="ww" and @lemma="zijn"] and node[@rel="predc" and @cat="np" and node[@rel="det" and @pt="lid" and @lemma="een"] and node[@rel="hd" and @pt="n" and @lemma="zin"]]]
XPATH
GrETEL• Greedy Extraction of Trees for Empirical Linguistics
• Query treebanks by example
GrETEL• Greedy Extraction of Trees for Empirical Linguistics
• Query treebanks by example
• First version=> only for LASSY treebank
• New release=> GrETEL for CGN treebank=> update based on user reviews
GrETEL• Example sentence
• Indicate relevant itemsof the sentence
• (Adapt XPath)• Select treebank
• Inspect results
• Parser (Alpino)
• Automatically generate XPath expression
• Present results
the user
OUTLINE• GrETEL in a nutshell
• GrETEL demoo Case studyo Search options
• Conclusions and future work
CASE STUDY• Verbs with fixed preposition
o E.g. Hij keek met een bang hartje naar de heks. ‘he was looking at the witch with a heavy heart .’
o VERB + (…+) PREP
LASSY:• Xpath query//node[@cat="smain" and node[@rel="hd" and @pos="verb" and @root="kijk"] and node[@rel="ld" and @cat="pp" and node[@rel="hd" and @pos="prep" and @root="naar"]]]
CASE STUDY• Verbs with fixed preposition
o E.g. Hij keek naar de heks. ‘he was looking at the witch .’
• Discontinuous constructions!o E.g. Hij keek met een bang hartje naar de heks.
‘he was looking at the witch with a heavy heart .’
o VERB + (…+) PREP
GrETEL ONLINE
INPUT
ANNOTATION MATRIX
ANNOTATION GUIDELINES
XPATH GENERATOR
Other treebank, other format …Hij keek met een bank hartje naar de heks
• CGN/node[@cat="smain" and node[@rel="hd" and @pt="ww" and
@lemma="kijken"] and node[@rel="ld" and @cat="pp" and node[@rel="hd" and @pt="vz" and @lemma="naar"]]]
• LASSY//node[@cat="smain" and node[@rel="hd" and @pos="verb"
and @root="kijk"] and node[@rel="ld" and @cat="pp" and node[@rel="hd" and @pos="prep" and @root="naar"]]]
Other treebank, other format …Hij keek met een bang hartje naar de heks
• CGN/node[@cat="smain" and node[@rel="hd" and @pt="ww" and
@lemma="kijken"] and node[@rel="ld" and @cat="pp" and node[@rel="hd" and @pt="vz" and @lemma="naar"]]]
• LASSY//node[@cat="smain" and node[@rel="hd" and @pos="verb"
and @root="kijk"] and node[@rel="ld" and @cat="pp" and node[@rel="hd" and @pos="prep" and @root="naar"]]]
TREEBANK SELECTION
RESULTSVerb plus fixed preposition
o E.g. Hij keek naar de heks. ‘A number of trees fell down.’
o VERB + (…+) PREP
4004 matches in 3881 sentences
RESULTS: table
RESULTS: data
RESULTS: trees
OUTLINE• GrETEL in a nutshell
• GrETEL demoo Case studyo Search options
• Conclusions and future work
SEARCH OPTIONS
Below annotation matrix
SEARCH OPTIONSGreen versus red word order in Dutch
o green: past participle – auxiliary De NAVO stelt dat ze er alles aan gedaan heeft
o red: auxiliary – past participleDe NAVO stelt dat ze er alles aan heeft gedaan
“The NATO claim that they have done everything in their power” (deredactie.be)
SEARCH OPTIONS
SEARCH OPTIONS
SEARCH OPTIONS
SEARCH OPTIONS
SEARCH OPTIONS
OUTLINE• GrETEL in a nutshell
• GrETEL demoo Case studyo Search options
• Conclusions and future work
CONCLUSIONS• GrETEL: search engine for Dutch treebanks
• Input = natural language example
• Output = sample of similar sentences
• Syntactic concordancer
• Available online (via Mozilla Firefox)
• No installation required
FUTURE WORK• GrETEL 2.0
o Include SoNaR corpus (ca 500M tokens)o More generic
• AfriBoomso GrETEL for Afrikaanso Include other treebank formats
CASE STUDY• Collective noun constructions
o E.g. Een aantal bomen zijn omgevallen. ‘A number of trees fell down.’
o DET + NOUN + PLURAL NOUN
• Discontinuous constructions!o E.g. Een groot aantal oude bomen zijn omgevallen.
‘A large number of old trees fell down.’
Thanks for your attention!
Try it yourself athttp://nederbooms.ccl.kuleuven.be/eng/gretel
Waaraan vs Waar … aan
Waar denk je aan ?//node[@cat="top" and node[@rel="--" and @cat="whq" and
node[@rel="whd" and @pos="adv"] and node[@rel="body" and @cat="sv1" and node[@rel="pc" and @cat="pp" and node[@rel="hd" and @pos="prep"]]]] and node[@rel="--" and @pos="punct"]] (4 results)
• Waar bemoei je je mee?• Wanneer gaat een koortsstuip over in epilepsie ?
Waaraan denk je ?//node[@cat="top" and node[@rel="--" and @cat="whq" and
node[@rel="whd" and @pos="pp"]] and node[@rel="--" and @pos="punct"]] (38 results)
• Waarom werken we ?• Waartoe verbind ik mij als ouder door dit formulier in te
vullen ?• Vanwaar die gulle hand van een Turkse overheid die in de
schulden zwemt ?
Hij klom de boom in//node[@cat="top" and node[@rel="--" and @cat="smain"
and node[@rel="hd" and @pos="verb"] and node[@rel="ld" and @cat="np" and node[@rel="det" and @pos="det"] and node[@rel="hd" and @pos="noun"]] and node[@rel="svp" and @pos="part"]] and node[@rel="--" and @pos="punct"]] (37 results)
• Door haar winst komt Clijsters de top-20 binnen .• In feite ging minder dan de helft van Dorsets de rivier
over .• Nederland gaat de bezettingstijd in .