Page "Phoneme" Paragraph 31

An example of neutralization is provided by the Russian vowels and.

These phonemes are contrasting in stressed syllables, but in unstressed syllables the contrast is lost, since both are reduced to the same sound, usually ( for details, see Vowel reduction in Russian ).

In order to assign such an instance of to one of the phonemes and, it is necessary to consider morphological factors ( such as which of the vowels occurs in other forms of the words, or which inflectional pattern is followed ).

In some cases even this may not provide an unambiguous answer.

A description using the approach of underspecification would not attempt to assign to a specific phoneme in some or all of these cases, although it might be assigned to an archiphoneme, written something like | A |, which reflects the two neutralized phonemes in this position.