American English in the last decade or more has manifested a phonetic change whereby what was previously a syllabic /n/ in the clusters /dnt/ and /tnt/ at the end of words has instead developed an epenthetic [ɛ] preceding it. Accordingly, whereas the older normative pronunciation of words like student, hadn’t, didn’t, and patent typically had no vowel before [n], now the younger generation of speakers inserts an unstressed open mid-vowel [ɛ] before it.

The explanation for this change has to do with the kind of language English is typologically, namely a consonantal language, and not a vocalic language. All languages of the world are divided into these two basic types. The vocalic languages have evolved through a series of phonological changes which seem to manifest general tendencies to change consonants to vowels, to use consonants as syllabics, to develop new syllables by vowel insertion, to simplify consonant sequences, etc. By contrast, the consonantal languages have maintained complex consonant clusters but have manifested a tendency to suppress the sonority of liquids and nasals. Vocalic languages evince a tendency to vocalize consonants, whereas the consonantal languages suppress the natural sonority of consonants.

Contemporary American English, as a consonantal language, by desyllabicating the nasal sonorant /n/ in the clusters /tnt/ and /dnt/, is thus just fulfilling its typological Bauplan. This is its teleological fate, as the long-term goal of change in language, as in evolution generally, is determined ultimately by the conformity of any individual change to the type of outcome that it implements.