Free Variation in Phonetics

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In phonetics and phonology, free variation is an alternative pronunciation of a word (or of a phoneme in a word) that doesn't affect the word's meaning.

Free variation is "free" in the sense that it doesn't result in a different word. As William B. McGregor observes, "Absolutely free variation is rare. Usually, there are reasons for it, perhaps the speaker's dialect, perhaps the emphasis the speaker wants to put on the word" (Linguistics: An Introduction, 2009).


"When the same speaker produces noticeably different pronunciations of the word cat (e.g. by exploding or not exploding the final /t/), the different realizations of the phonemes are said to be in free variation." (Alan Cruttenden, Gimson's Pronunciation of English, 8th ed. Routledge, 2014)

Free Variation in Context

"Sounds that are in free variation occur in the same context, and thus are not predictable, but the difference between the two sounds does not change one word into another. Truly free variation is rather hard to find. Humans are very good at picking up distinctions in ways of speaking, and assigning meaning to them, so finding distinctions that are truly unpredictable and that truly have no shade of difference in meaning is rare." (Elizabeth C. Zsiga, The Sounds of Language: An Introduction to Phonetics and Phonology. Wiley-Blackwell, 2012)

"[F]ree variation, however infrequent, can be found between the realizations of separate phonemes (phonemic free variation, as in [i] and [aI] of either), as well as between the allophones of the same phoneme (allophonic free variation, as in [k] and [k˥] of back)... 

"For some speakers, [i] may be in free variation with [I] in final position (e.g. city [sIti, sItI], happy [hӕpi, hӕpI]). The use of final unstressed [I] is most common to the south of a line drawn west from Atlantic City to northern Missouri, thence southwest to New Mexico." (Mehmet Yavas, Applied English Phonology, 2nd ed. Wiley-Blackwell, 2012)

Stressed and Unstressed Syllables

"There can... be free variation between full and reduced vowels in unstressed syllables, which also has to do with related morphemes. For example, the word affix can be a verb or a noun, and the form carries stress on the final syllable and the latter on the initial one. But in actual speech, the initial vowel of the verb is actually in free variation with schwa and the full vowel: /ə'fIks/ and /ӕ'fIks/, and this unstressed full vowel is the same as that found in the initial syllable of the noun, /ӕ'fIks/. This kind of alternation is probably due to the fact that both forms actually occur, and they are instances of two lexical items that are not just formally but also semantically closely related. Cognitively, when only one is actually evoked in a given construction, both are probably activated nevertheless, and this is the likely source of this free variation." (Riitta Välimaa-Blum, Cognitive Phonology in Construction Grammar: Analytic Tools for Students of English. Walter de Gruyter, 2005)

Extragrammatical Factors

"The fact that variation is 'free' does not imply that it is totally unpredictable, but only that no grammatical principles govern the distribution of variants. Nevertheless, a wide range of extragrammatical factors may affect the choice of one variant over the other, including sociolinguistic variables (such as gender, age, and class), and performance variables (such as speech style and tempo). Perhaps the most important diagnostic of extragrammatical variables is that they affect the choice of occurrence of one output in a stochastic way, rather than deterministically." (René Kager, Optimality Theory. Cambridge University Press, 1999)