Cascade Effect

The cascade effect (also known as the “rhaeadr effect” from the Welsh word for “waterfall”) occurs when a problem at one level of linguistic organization also produces problems at other levels. An example from English is when the phonological problem of an inability to produce word final consonant clusters also affects the ability to produce morphological endings on words closed with a consonant. Thus, regular noun plurals (cats), possessive marking on nouns (cat’s), third-person singular present-tense marking on verbs (walks), and regular past-tense and participle-marking on verbs (walked) are all lost.

Likewise, a phonological pattern of final consonant deletion in French would lead (among other things) to the inability to mark the distinction between masculine and feminine forms of many adjectives (bon–bonne [bɔ̃]–[bɔn] “good”). For languages ...