Rules for English Aspiration

English has aspirated plosives. This is also the case in German, but Dutch is a Germanic language which lacks aspirated plosives. Plosives are aspirated when they occur before a stressed vowel, but usually not aspirated after /s/. In some cases, however, this rule does not apply.

The word distant has an unaspirated plosive. The word consists of two syllables, di.stant. The plosive occurs before an unstressed vowel and after the alveolar fricative /s/. However, in the case of destroy, the plosive occurs before a stressed vowel but aspiration does not apply because it follows the alveolar fricative. Aspiration occurs in tone but not in stone. It also occurs in port but not in sport.

In the word distrust, the plosive is aspirated. The reason is that the morphemes dis and trust form the syllable boundary. The aspirated plosive of trust is preserved in the word distrust. The morpheme boundary thus preserves aspiration.

Normally English plosives are not aspirated when they follow the voiceless alveolar fricative. However, words such as distrust do not follow this rule because they consist of morphemes which syllabify the world differently. In the word distant, the plosive is the second segment of the second syllable. In distrust, however, it is the first plosive of the second syllable.