Collocations

1. Collocations • Some typical collocations • as long as • with respect to • familial high-density lipoprotein deficiency • point the way

2. Collocations • Collocations are recognised at three levels: • Token stream • Word level • Structure level • The point of recognition varies depending on the variability and the potential ambiguity

3. Token Stream the disease known as familial high - density lipoprotein deficiency is a result An unconditional collocation - that is, it can’t be anything else - is found by dictionary lookup while the text is being turned into tokens, and the tokens are combined into a single token the disease known as FHLD is a result

4. Word Level The collocation is seen at the word level, when structure building has begun but before the PARSE operators have put out symbols. “As long as” can be caught by only knowing the preceding symbol.

5. Word Level The result of recognising the collocation at this point is that the parse chain is shrunk by pruning the structure before parsing becomes active

6. Variable Collocations • A collocation like “point the way” can appear in many forms, making it unsuitable for recognition at the word level - • he was pointing the way • the sign pointed the way • the way forward was pointed • Other collocations allow variable symbols within them so need to be replaced by a structure.

7. Structure Level This structure is recognizing a collocation and turning it into a structure. Detection of collocations at this level is much more expensive, but also much more discriminating

8. Which Level Unconditional collocations can be caught at the token level, but there are relatively few of these Some collocations only need a light dusting of analysis using neighboring symbols - these are caught at the word level Some collocations are worth catching, but involve a lot of structure building to be sure they are what is meant