Pattern of Schwa Deletion in English

Unstressed vowels in English often delete. The deleted vowel is always a schwa and may thus be termed schwa deletion. In words which end with the suffix -ly, schwa deletion often occurs.

Schwa deletion occurs in the following words:

basically

chronically

dynamically

historically

idealistically

musically

philosophically

physically

pyschologically

realistically

However, schwa deletion usually does not occur in these words:

accidentally

communally

finally

formally

internally

materially

mentally

normally

terminally

totally

Though the two sets of words both end with -ally, they are different. In the set with vowel deletion, the root ends with a [k]. This is a velar plosive and is classified as [-coronal]. However, in the second set, the root ends with [l], [n] and [t]. These sounds are all [+coronal]. With coronal sounds, schwa deletion usually does not occur.

In words such as basically, dynamically and physically, schwa deletion creates a consonant cluster which is very common in the English syllable onset. It occurs in words such as clay, clean and cloud. However, no consonant clusters occur with adjacent coronal consonants.

Schwa deletion is a common process in English. However, it does not occur in all possible environments. Between coronal consonants, it is far less common than in other consonants.