Natural language processing is a subfield of artificial intelligence. It studies the problems inherent in the processing and manipulation of natural language, but not, generally, [[natural language understanding. It should not be confused with computational linguistics, which is in the ___domain of linguistics.
The major tasks in NLP are:
Some problems which make NLP difficult:
- Word boundary detection
- In spoken language, there are no gaps between words; where to place the word boundary often depends on what choice makes the most sense gramatically and given the context.
- Word sense disambiguation
- Any given word can have several different meanings; we have to select the meaning which makes the most sense in context.
- Syntactic ambiguity
- The grammar for natural languages is not unambiguous, i.e. there are often multiple possible parse trees for a given sentence. Choosing the correct one usually requires semantic and contextually information.
- Speech acts and plans
- Sentences often don't mean what they literally mean; for instance the correct answer to "Can you pass the salt?" is to pass the salt, not "yes". Or again, if a class was not offered last year, the correct answer to the question "How many students failed the class last year?" is "The class was not offered last year", not "None".