Текст № 5

Difference between a Vowel and a Semivowel

While there are a number of similarities, diphthongs are not the same as a combination of a vowel and an approximant or glide. Most importantly, diphthongs are fully contained in the syllable nucleus while a semivowel or glide is restricted to the syllable boundaries (either the onset or the coda). This often manifests itself phonetically by a greater degree of constriction.

Nonetheless, in practice the choice of treating a diphthong or diphthong-like element as a single phoneme, a sequence of two vowels or a combination of a vowel and a glide is based not on the phonetic nature of the diphthong but on systemic properties of the language. The following are examples of systemic characteristics that tend to determine which analysis is chosen:

• The presence of alternations among related words or related dialects between diphthongs and monophthongs, sequences of vowel and consonant, or sequences of two vowels in separate syllables

• The restrictions on the diphthongs that can occur

• The existence of glides such as /w/ and /j/ as separate phonemes in the language

• The behavior of the diphthong when a vowel directly follows

• The historical origin of the diphthong