If segments appear in the same position but the mutual substitution
does not result in change of meaning, they are said to be in free variation.
A case in point is the two different segments at the beginning of wh-words
in English. In [wen] and [
en],
the two initial sounds appear in the same environment, but the two forms
are not a minimal pair, because they are two different dialectal variants
in pronouncing the same word when. Similarly, in [
i:k
n
miks]
and [eknmiks]
the two initial vowels are in free variation. Segments in free variation
are generally dialectal variations.
