Direction of Assimilation in Child Consonant Harmony

In child language, consonants often assimilate in primary place of articulation across intervening vowels. In adult language, primary place assimilation occurs only between adjacent consonants. In both cases, the first consonant usually assimilates to the second. The standard analysis of directionality of local assimilation in Optimality Theory uses positional faithfulness to protect the second consonant. In this paper we argue that directionality in child language assimilation is due not to positional faithfulness, but to a markedness constraint that specifies that a consonant preceding a dorsal must agree in place of articulation with it. Along with directionality, this constraint accounts for cases in which dorsals, but not labials, trigger assimilation, which occurs in Korean as well as in child language. Differences between the attested types of assimilation in adult and child language can be explained by differences in how positional faithfulness applies in the two domains.