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 with relatively free word order but with rich inflectional systems that denote sentence categories (such as subject or object), a pattern of loss of final syllable affects the ability to signal sentence categories, and such a syntactic effect would naturally also impinge on sentence semantics. For example, Lithuanian marks noun cases with paradigms of endings that can be single vowels or combinations of vowels and consonants.

These inflectional morphemes distinguish seven grammatical cases in the singular and the same seven in the plural (nominative, accusative, genitive, dative, instrumental, locative, vocative—for example, brólis (“brother”) has the following forms in the singular: brólis, brólio, bróliui, brólį, bróliu, brólyje, bróli. Thus, the loss at the morphological level of these case markings due to a problem at the phonological level has major implications for the ability to signal meaning at the sentence level.

The cascade effect does not always start at the phonological level, however. An articulatory problem (such as the ability to produce a typical English approximant—[ɹ]), may result in the neutralization of the phonological contrast between /r/ and /w/, which in turn cascades over into lexical semantics through potential confusions between word pairs such as run–won and ray–way. Simplification at the morphological level often cascades over into the syntax and then into the sentence semantics.

For example, if the distinction between nominative and accusative forms of the German determiner are merged (e.g., using the nominative for both), then it would not be possible to interpret the sentence *der Mann sah der Hund, which in standard German could represent either der Mann sah den Hund[Page 316] (“the man saw the dog”) or den Mann sah der Hund (“it was the man that the dog saw”). (Naturally, the same problem would occur if the determiner had been neutralized to the accusative form.)

Finally, one can consider a syntactic problem source—for example, use of random word order in a language requiring fixed work order, affecting sentence semantics. Thus, in Italian, the subject is distinguished from the object through being placed before, instead of after, the verb: il gatto ha visto il cane (“the cat saw the dog”). If the speaker has a problem with word order, then various alternatives might be produced: il cane ha visto il gatto (acceptable Italian but meaning “the dog saw the cat”), *gatto il visto ha cane il, *visto il gatto ha cane il, etc., all meaningless).

...