Why estimating vocabulary size by counting words is (nearly) impossible
A few days ago, I expressed skepticism about a claim that "the human lexicon has a de facto storage limit of 8,000 lexical items", which was apparently derived from counting word types in various sorts of texts ("Lexical limits?", 12/5/2015). There are many difficult questions here about what we mean by "word", and what it means to be "in" the lexicon of an individual or a language — though I don't see how you could answer those questions so as to come up with a number as low as 8,000. But today I'd like to focus on some of the reasons that even after settling the "what is a word" questions, it's nearly hopeless to try to establish an upper bound by counting "word" types in text.
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