Knowing a Word Is Not an All-or-Nothing Matter

A third limitation is that our definition of words does not take into account the fact that some words have multiple senses and sometimes even meanings. Words like ‘mind, miss, sack, second’ have several meanings that are unrelated to each other. Goulden et al. (1990) estimated that 15 percent of the entries in Webster’s Third were homographs (word with multiple meanings), of which two thirds did not differ substantially from the previous entry (i.e., the difference was a difference in sense rather than meaning). So, a reasonable estimate would be that 5% of the words are ambiguous in their meaning and our measure has no way to assess whether the participants were familiar with the various meanings. Even worse, our assessment says nearly nothing about how well the participants know the various words. They were only asked to select the words they knew. Estimates of vocabulary size are smaller if more demanding tests are used, as can be seen in Table 3 [e.g., compare the estimate of Zechmeister et al. (1995) to that of D’Anna et al. (1991) and the estimate of Milton and Treffers-Daller (2013) to that of Goulden et al. (1990)]. Indeed, understanding the meaning of words is not a binary, all-or-nothing phenomenon but a continuum involving multiple aspects (Christ, 2011). As such, our estimates should be considered as upper estimates of word knowledge, going for width rather than depth. The estimates also deal with receptive word knowledge (understanding words other people use). As indicated above, productive knowledge is thought to be roughly half of receptive word knowledge.