Using NLTK Part-of-Speech Tagger

Learn about the Part-of-Speech tagger in the NLTK library. Gain hands-on experience using parts of speech from the NLTK library.

NLTK taggers

The NLTK library provides different ways to implement POS tagging, including CRFTagger, StanfordPOSTagger, BrillTagger, etc., but in this lesson, we'll focus on the two most commonly used implementations:

  • The perceptron model, which is also the default tagger

  • The HMM tagger

NLTK default classifier

By default, NLTK uses a perceptron tagger, more specifically a greedy averaged perceptron tagger. This is a greedy averaged perceptron tagger, which is simply a pre-trained feed-forward neural network that guesses a tag, adjusts the weights according to whether the guess was correct, and averages the weight adjustments over the number of iterations. This creates a model that is essentially a dictionary of weights associated with the input features (or input word/sentence), that can then output the associated solution in ...