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 a different pronunciation doesn't result in a different word or meaning. This is possible because some allophones and phonemes are interchangeable and can be substituted for each other or said to have overlapping distribution.

Definition of Free Variation

Alan Cruttenden, author of Gimson's Pronunciation of English, offers a clear definition of free variation by giving an example: "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," (Cruttenden 2014).

Why Free Variation Is Hard to Find

Most subtle differences in speech are intentional and meant to alter meaning, which makes free variation less common than you might think. 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," (McGregor 2009).

Elizabeth C. Zsiga echoes this, explaining also that free variation is not predictable because it is context-dependent and could be due to any number of environmental factors. "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," (Zsiga 2013).

How Predictable Is Free Variation?

It should not be assumed, however, that because free variation is not necessarily predictable that it is entirely unpredictable. René Kager writes, "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," (Kager 2004).

Where Free Variation Is Found

There is a good deal of flexibility, both grammatically and geographically, regarding where free variation can be found. Take a look at some of the patterns. "[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)," begins Mehmet Yavas. "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," (Yavas 2011).

Riitta Välimaa-Blum goes into more detail about exactly where free variation of phonemes can occur in a word: "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," (Välimaa-Blum 2005).


  • Cruttenden, Alan. Gimson's Pronunciation of English. 8th ed., Routledge, 2014.
  • Kager, René. Optimality Theory. Cambridge University Press, 2004.
  • McGregor, William B. Linguistics: An Introduction. Bloomsbury Academic, 2009.
  • Välimaa-Blum, Riitta. Cognitive Phonology in Construction Grammar. Walter de Gruyter, 2005.
  • Yavas, Mehmet. Applied English Phonology. 2nd ed., Wiley-Blackwell, 2011.
  • Zsiga, Elizabeth C. The Sounds of Language: An Introduction to Phonetics and Phonology. Wiley-Blackwell, 2013.
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Nordquist, Richard. "Free Variation in Phonetics." ThoughtCo, Aug. 27, 2020, Nordquist, Richard. (2020, August 27). Free Variation in Phonetics. Retrieved from Nordquist, Richard. "Free Variation in Phonetics." ThoughtCo. (accessed May 29, 2023).