Free Variation

While the above generalizations are typically solid, there are two instances in English where the last two, (c) and (d), are violated. In the first, we see cases in which the allophones of a phoneme occur in the same environment. This is a violation of (c), because it does not follow the principle that the allophones should be in complementary distribution. For example, the final stops of American English are normally unreleased and unaspirated as in bake [bek⸣], dip [dɪp⸣], etc. However, a speaker may pronounce these items with released final stops. Although these alternative productions are possible, they do not create any change in meaning. That is, in different speakers’ pronunciations, we can find the released and unreleased allophones in an overlapping distribution. But, since the meaning of the word does not change, this is termed a free variation.

The second type of free variation is related not to the allophones of the same phoneme, but to the realizations of different phonemes. For example, the sounds [i] and [ε] belong to separate phonemes, /i/ and /ε/ respectively, because English possesses minimal pairs such as bead [bid] – bed [bεd], Pete [pit] – pet [pεt]. Since the change in meaning in these pairs of words is due to the substitution of these vowels for each other, there can be no question about their contrastiveness. However, for certain vocabulary items such as economics, which may be pronounced as [εkənamɪks] or [ikənamɪks], the two vowels in question occur in an overlapping distribution but without creating a change in meaning. A similar case can be cited between [aɪ] and [i], which are also normally in contrast. Thus, in cite [saɪt] versus seat [sit] the meaning change is due to these two vowels being in contrast. However, alternative pronunciations for items such as either ([iðɚ] or [aɪðɚ]), neither ([niðɚ] or [naɪðɚ]) clearly show them in free variation (overlap but no meaning change). To summarize, we can say that free variation, however infrequent, can be found between the realizations of separate phonemes (phonemic free variation, as in [i] and [aɪ] of either), as well as between the allophones of the same phoneme (allophonic free variation, as in [k] and [k⸣] of back).