POS-Tagger is incredibly slow

Question

I am using nltk to generate n-grams from sentences by first removing given stop words. However, nltk.pos_tag() is extremely slow taking up to 0.6 s

Answer 1

nltk pos_tag is defined as:
from nltk.tag.perceptron import PerceptronTagger
def pos_tag(tokens, tagset=None):
    tagger = PerceptronTagger()
    return _pos_tag(tokens, tagset, tagger)

so each call to pos_tag instantiates the perceptrontagger module which takes much of the computation time.You can save this time by directly calling tagger.tag yourself as:

from nltk.tag.perceptron import PerceptronTagger
tagger=PerceptronTagger()
sentence_pos = tagger.tag(word_tokenize(sentence))