Phonological constraints
The first type of constraint on morphological productivity is phonological. We have already seen that phonology is a factor in the distribution of allomorphs. It is therefore not surprising that phonology constrains morphology in other ways. Bauer identifies three types of phonological constraints on productivity: (i) those that depend on the segmental make-up of the base; (ii) those that depend on the suprasegmental make-up of the base, including stress placement; and (iii) those that depend on the number of syllables in the base.
An example of the first type discussed by Bauer is the Modern Hebrew pet-name suffix -le, borrowed from Yiddish. It can only attach to bases ending in a vowel (Glinert 1989: 437):
As an example of the second type, where it is the suprasegmental make-up of the base that matters, Bauer presents -al suffixation in English. This suffix may attach only to verbs that are stressed on the final syllable, as seen in the examples in (8). (Bauer notes that the apparent exception burial should not be considered a counterexample, because it has a different etymological source.)
(8) acquittal, arrival, denial, dismissal, rebuttal, referral, revival
Bauer illustrates the last type, instances where the number of syllables in the base is important, with Tzutujil (Dayley 1985: 212), where the suffix -C1oj ‘-ish’ may attach only to monosyllabic adjectives, as in raxroj ‘greenish’.
