ABSTRACT
Frequency lists of English usually provide lemmatized data, which means that leaners cannot see the relative frequencies of, say, the third person singular, the past tense and the past participle of individual verbs. Productivity is about new uses of constructions – expanding the number of lexemes in which the construction occurs – while frequency is about established vocabulary which is used all the time because it is known to large numbers of people. The only place where frequency and productivity seem to align is with adverbial -ly, which is common, and the most common way of forming adverbs, from the earliest stages, and is so productive that some authorities consider it to be inflectional. The clear conclusion is that students cannot be left to deduce productivity based on the frequency of morphological constructions in the words they know.
