Dealing with Ambiguity in Natural Language Processing: The Role of Lexemes

syndu | Oct. 2, 2023, 7:53 p.m.

Create an image representing the concept of managing ambiguity in Natural Language Processing through the use of lexemes.

Dealing with Ambiguity in Natural Language Processing: The Role of Lexemes

Hello, dear readers. In our previous blog post, we discussed the concept of lexemes in the SpaCy library. Today, we're going to delve deeper into this topic and explore how lexemes can help us deal with ambiguity in natural language processing (NLP).

Ambiguity in Language

Language is inherently ambiguous. The same word can have different meanings depending on the context in which it is used. For example, consider the word "bank". It can refer to a financial institution where people deposit or borrow money, or it can refer to the land alongside a body of water.

This ambiguity can pose challenges in NLP. When a machine reads the sentence "The money is in the bank", how does it know whether "bank" refers to a financial institution or the side of a river? This is where lexemes come in.

Lexemes and Sense Disambiguation

In SpaCy, a lexeme is a word type with no context. It doesn't have any part-of-speech, dependency or entity labels, and it always only has a single lemma (base form of the word). This means that, in the vocabulary of a language model, the word "bank" will be represented by a single lexeme, regardless of the context in which it is used.

This doesn't mean that SpaCy ignores the context of words. On the contrary, when SpaCy processes a text, it doesn't just look at the individual words (or lexemes), but also at the surrounding words. This allows it to assign part-of-speech tags, dependency labels, and entity labels that reflect the context of each word.

In other words, while the lexeme for "bank" is always the same, the token for "bank" in the sentence "The money is in the bank" will have different attributes than the token for "bank" in the sentence "The boat is parked on the bank".


In conclusion, lexemes provide a powerful and efficient way to handle and analyze words in NLP, but they are just one piece of the puzzle. Dealing with ambiguity in language also requires looking at the context of words, which is where other features of SpaCy, such as part-of-speech tagging and dependency parsing, come into play.

Stay tuned for more deep dives into the world of NLP and SpaCy!

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