Word Frequencies and Ngrams#

Because word frequencies and combinatorics are useful for many purposes, the following Reader methods are defined:

word_frequencies([keep_case, participants, ...])

Return word frequencies.

word_ngrams(n[, keep_case, participants, ...])

Return word ngrams.

For both word_frequencies() and word_ngrams():

  • They have the same optional arguments participants, exclude, and by_files as words(), tokens(), utterances() do.

  • They have the optional argument keep_case to specify whether upper/lowercase distinction should be kept or collapsed in counting words or ngrams.

  • They return Counter objects, which naturally represent a mapping from words or ngrams to their counts, and have useful methods for working with count data.

For illustration, let’s check out some of the word trigrams in Eve’s data from Brown. To make it slightly more interesting, we are going to look at child speech and child-directed speech separately.

>>> import pylangacq
>>> url = "https://childes.talkbank.org/data/Eng-NA/Brown.zip"
>>> eve = pylangacq.read_chat(url, "Eve")
>>> trigrams_child_speech = eve.word_ngrams(3, participants="CHI")
>>> trigrams_child_speech.most_common(10)  # A collections.Counter object has the method ``most_common``.
[(('grape', 'juice', '.'), 74),
 (('another', 'one', '.'), 55),
 (('what', 'that', '?'), 50),
 (('a', 'b', 'c'), 47),
 (('right', 'there', '.'), 45),
 (('in', 'there', '.'), 43),
 (('b', 'c', '.'), 42),
 (('hi', 'Fraser', '.'), 39),
 (('I', 'want', 'some'), 39),
 (('a', 'minute', '.'), 35)]
>>> trigrams_child_directed_speech = eve.word_ngrams(3, exclude="CHI")
>>> trigrams_child_directed_speech.most_common(10)
[(("that's", 'right', '.'), 178),
 (('what', 'are', 'you'), 149),
 (('is', 'that', '?'), 124),
 (('do', 'you', 'want'), 104),
 (('what', 'is', 'that'), 99),
 (('are', 'you', 'doing'), 94),
 (("what's", 'that', '?'), 92),
 (('would', 'you', 'like'), 89),
 (('what', 'do', 'you'), 89),
 (('is', 'it', '?'), 89)]

Just this very brief result using word trigrams appears to show a contrast between various demands being frequent in child speech, versus the dominant usage of confirmation and attempts to get the child’s attention using questions in child-directed speech.