1. Translating Collocations for Bilingual Lexicons
Collocations (idiomatic multi-word expressions) difficult to translate
semantically opaque
cannot be translated word-by-word
a major obstacle to second language acquisition
Example: demonstrate support  prouver son adhésion (prove adherence)

2. The Champollion approach
Input: Large parallel corpora
Output: List of collocations in each language, and equivalence mappings between these collocations
The method is statistical and language-independent

3. Algorithm Align sentences across corpora
Extract collocations from co-occurrence
Identify all words that frequently appear across a source collocation
Iteratively consider and score combinations of those words
Select best set of words for the translation
Determine word order and fill in prepositions

4. Sample translations additional costs  coûts supplémentaires
affirmative action  action positive
free trade  libre-échange
freer trade  libéralisation … échanges
take … steps  prendre … mesures
stock market  bourse

5. Evaluation results
Corpus of 3.5 million words, collocations selected from the same corpus: 78%
Corpus of 8.5 million words, collocations selected from the same corpus: 74%
Corpus of 3.5 million words, collocations selected from a different corpus: 65%

6. Conclusion Champollion provides for collocation translation Robust
Language-independent
Requires no tools
But: Requires parallel corpora