The role of phonemic and subphonemic cues in morphological learning

Abstract Building upon recent discoveries highlighting the direct interplay between phonetics and morphology in production, perception, and comprehension, our study adds another dimension to this area of research: language learning. We use as template the case of English word-final /s/, where segment duration has been shown to serve as a critical cue for morphological category differentiation (non-morphemic, suffix, or clitic). In a study with German adults, employing an artificial language learning paradigm, we compared the ability to learn the distinction between singular and plural forms, where in one group, singular and plural were distinguished by phonemic content (/p/ vs. /f/), and in two other groups, singular and plural were distinguished by durational differences varying in length (/f/). The experimental design consisted of a training phase, followed by a number decision task involving new items. We employed a mouse-tracking paradigm, which allowed us to not only assess the success rate, but also analyze the reaction times and trajectories of participants’ responses in detail. Our findings reveal that the artificial language relying on the phonemic cues is learned easily, while learners of the artificial language relying on the subphonemic cues lag behind but apparently show signs of initial learning. Our results contribute to the understanding of the intricate relationship between phonetics and morphology, shedding light on the role of subphonemic information in linguistic categorization.