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 participle

De 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 .