free variation

Sometimes variations of a phoneme occur in the same position but do not cause a difference in meaning ; they are in free variation , i.e. one can be replaced by the other without causing a difference in function or meaning, i.e. without being distinctive.

Free variation is a term that is used to describe the observation that two forms occur in the exact same position without any change of function or meaning and without being perceived by native speakers as wrong. The pronunciation of the initial sound in the English lexeme economics as either /i:/ or /ɛ/ is an example of free variation as a phonemic phenomenon; two sounds which in other contexts are phonemes, i.e. distinctive speech sounds, are used here in the exact same context, i.e. the word 'economics' without causing any change of function or meaning and are equally acceptable here to the native speaker.

The concept of free variation was first described in phonology by the Russian Prague School structuralist Nikolai Sergeyevich Trubetzkoy for free variation between speech sounds. It was not intended or defined to be applied to the level of morphology.

Ganz umgekehrt sind im Japanischen r und l zwar vertauschbar, aber unfähig, eine distinktive Opposition zu bilden: in jedem beliebigen Wort kann l durch r ersetzt werden und umgekehrt, ohne daß dadurch irgendeine Bedeutungsänderung entstehen würde. (Trubetzkoy 1939:32)

Note that Nikolai Trubetzkoy is also the linguist who defined the concept of the phoneme in his book “Grundzüge der Phonologie” (1939), English edition: “Principles of Phonology”.

Reference: Trubetzkoy, Nikolai Sergeyevich. 1939. “Grundzüge der Phonologie”. Travaux du Cercle Linguistique de Prague 7.