Why are the sounds Я, Ё, Ю, and Е not considered diphthongs in Russian even though they consist of two sounds?

Question

In Russian, the so-called 'soft vowels' (я, ё, ю, е) combine a semivowel ('й') with a vowel, which might seem like diphthongs. However, they are not classified as diphthongs in Russian phonetics. This question explores why.

Answer 1

Although the Russian vowels я, ё, ю, and е combine two sounds ('й' + vowel), they are not considered diphthongs because diphthongs are defined as two vowels pronounced together like a single vowel. In Russian, the first element ('й') is a semivowel or glide and is treated as a consonant in Russian phonetics.

1. Why 'й' Is Not a Vowel:
2. The Russian letter 'й' (short и, or и краткое) behaves like the English semivowel 'y,' but with some differences in articulation. It is voiced and often articulated in the same position as the palatalized fricative 'хь' (x’), especially at the beginning of a word or between vowels.
3. Examples of Semivowel Behavior:
4. In words like 'моя' ([maˈja]) or 'съел' ([sʲjel]), 'й' serves as a transition between the preceding and following vowels, but it remains a consonant sound.
5. End-of-Word Articulation:
6. At the end of a word, 'й' may lose its voicing, as in 'вий' ([vij] or [vixʲ]) depending on careful or casual speech. However, this does not turn it into a vowel or part of a diphthong.

By treating 'й' as a consonant, Russian phonetics maintains a clear distinction between semivowels and true vowels. Understanding this nuance is key to mastering Russian pronunciation.