Lexico mental

Lecture 12: The Mental Lexicon
The mental lexicon differs radically from a dictionary. There are so many words and they are found so fast. Native speakers can recognize a word of their language in 200ms or less and can reject a non-word sound sequence in about half a second. When I showed you the non-words last lecture, it took you very little time to reject them as words. This speed is astonishing given how many words you would have to search through if you systematically examined the contents of your mental lexicon in order to reject such non-words. Just how many words are we talking about? Adults usually grossly underestimate the size of their vocabulary, guessing that it is between 1 and 10 percent of the real level. The French writer Georges Simenon was reported to have said that he made his style as simple as possible because he had read that over half the people in France used no more than a total of 600 words. He also claimed to have slept with 10,000 women. Aitchison suggests that at the very least he should exchange the numbers of words and women, but that 10,000 would still underestimate the vocabulary of an educated adult.
In a 1940 study Seashore & Erickson estimated that an educated adult knows more than 150,000 words and be able to use 90% of these. To arrive at this figure they prepared a list of 1,320 words by taking every third word down in the first column of every left hand page of the 1937 edition. They divided the list into four and asked hundreds of college students to define them and use them in illustrative sentences. The proportions correct were applied to the overall number of words in the whole dictionary to produce the overall total of 150,000 words. Some of the problems with this procedure are the definition of a 'word' and the 'big dictionary effect'.
The reading vocabulary of the average American high school graduate has been assessed at 40,000 words. If proper names of people and places, ands idiomatic expressions are included