When acquiring the English plural, children correctly produce plural words long before they develop an understanding of morphological structure. When acquiring Sesotho noun prefixes, children are aware of the multiple constraints governing variation from a young age. Both of these cases raise questions about the Shin and Miller (2022) account of…

When linguistic input contains inconsistent use of grammatical forms, children produce these forms more consistently, a process called "regularization." Deaf children learning American Sign Language from parents who are non-native users of the language regularize their parents' inconsistent usages. In studies of artificial languages…