A term used in LINGUISTICS to refer to the relationship which exists between the alternative FORMS, or VARIANTS, of a linguistic UNIT. The usual symbol for alternation is ~. In PHONOLOGY, for example, the related VOWEL QUALITIES of such words as telegraph ~ telegraphic, receive ~ reception are sometimes described as alternants, as are the various ALLOPHONES of a PHONEME. The term has had particular currency in MORPHOLOGY, however, where ‘morphemic/morpheme alternant’ is another term for allomorph, and where various subtypes have been distinguished. For example, ‘phonologically conditioned alternants’ are illustrated in the various forms of the plural MORPHEME (/-S/, /-Z/, /-IZ/), which are predictable from the preceding phonological context (‘MORPHOPHONEMIC alternants’). ‘Grammatically conditioned alternants’ are cases where there is no such rationale, the occurrence of an alternant depending entirely on the particular morphemes which occur in its environment, as in the various forms of the past participle in English (frozen, jumped, etc.). SUPPLETION is another category of alternation, referring to a morpheme lacking any regular phonological correspondence with other forms in a PARADIGM, as in go ~ went. In SYNTAX, examples of sets of alternants can be seen in the various grammatical CATEGORIES, such as TENSE (e.g. present ~ past ~ future).