S NP VP NNP NNP NNP VBZ NP Buffalo buffaloes Buffalo buffaloes JJ JJ NNP NNS Buffalo buffalo Buffalo buffaloes Soln:- This output is from the Stanford parser. There are probabilistic parsers which omit the verb completely for this sentence! Following facts may be kept in mind to analyse the behaviour of the probabilistic parser as depicted in the current output: is most likely either NNP (proper noun) or NN in sentence “Buffalo” beginning position. We cannot say evidence is stronger. However since probabilistic parsers are almost always trained on PENN Treebank which is nothing but the bracketed wall street journal corpora which in turn is financial domain corpus, is most likely the place “Buffalo” near Niagara. “Buffalo” That is why we see that the POS tag for is all correct as NNP. “Buffalo” is unlikely to have any evidence of being used as a verb in “buffalo” training corpus . This explains why neither of the two have been “buffalo” given any verb tag. It is difficult to explain why the which is in the fourth position “buffaloes” gets a VBZ tag most likely this is caused by the coercion of English plurals with third person singular number present tense verb forms. The second NP with JJ JJ NP NNS is like the black Buffalo “large buffaloes” and comes from a set of rules of the form
S NP VP NNP NNP NNP VBZ NP Buffalo buffaloes Buffalo buffaloes JJ JJ NNP NNS Buffalo buffalo Buffalo buffaloes Soln:- This output is from the Stanford parser. There are probabilistic parsers which omit the verb completely for this sentence! Following facts may be kept in mind to analyse the behaviour of the probabilistic parser as depicted in the current output: “Buffalo” is most likely either NNP (proper noun) or NN in sentence beginning position. We cannot say evidence is stronger. However since probabilistic parsers are almost always trained on PENN Treebank which is nothing but the bracketed wall street journal corpora which in turn is financial domain corpus, “Buffalo” is most likely the place “Buffalo” near Niagara. That is why we see that the POS tag for “Buffalo” is all correct as NNP. “buffalo” is unlikely to have any evidence of being used as a verb in training corpus . This explains why neither of the two “buffalo” have been given any verb tag. It is difficult to explain why the “buffaloes” which is in the fourth position gets a VBZ tag most likely this is caused by the coercion of English plurals with third person singular number present tense verb forms. The second NP with JJ JJ NP NNS is like the “large black Buffalo buffaloes” and comes from a set of rules of the form