LEXEME is the term used in Linguistics to refer to a word (a minimal unit of language) with a distinctive meaning (a semantic value) and often a specific cultural concept attached to it.
banana, love, animal, run
These are all lexemes.
Lexemes can be seen as the basic elements of a language.
Importantly, a single lexeme can have different forms which are sometimes quite different.
forms of the lexeme: love (verb)
love, loves, loved, loving
forms of the lexeme: crown (noun)
crown, crowns, crown’s, crowns’
forms of the lexeme: good (adjective)
good, better, best
The English lexeme which holds the record for most forms is be. The absolute minimum number of separate forms it has is 12:
am, are, aren’t, been, be, being, is, isn’t, was, wasn’t, were, weren’t.
However, in some other languages, (Sanskrit, for example) the number of forms for a verb lexeme is in the high hundreds, and for some others (Turkish, for example) it is in the thousands.
Lexemes and TEFL
The question is then, how does this affect the teacher? Should you be teaching your class about lexemes?
With by far the majority of classes it is probably not necessary to even mention the word lexeme in your class. While your students will certainly need to know a lexeme and its forms, by talking about lexemes as such you will likely just serve to confuse them.
Instead, we’d suggest talking about a root word and its forms:
forms: dog, dogs, dog’s, dogs’
and so on. This keeps things simple.
Vocabulary and TEFL – a general look at vocabulary in English
Words in English – what it means to be a word in English