Agreement can facilitate learning of noun class systems

Agreement, a systematic formal mapping between linguistic elements, adds redundancy to languages (e.g., in ‘she writes’ the -s adds no information), and yet is crosslinguistically prevalent. Here, we suggest that agreement may be functionally advantageous by providing additional cues for language learning. We conducted an artificial language learning experiment to test whether agreement, and especially, alliterative agreement – where the agreement is expressed by repetition of the same form, can facilitate learning of noun classes (e.g., ‘masculine’/’feminine’). To this end, we compared the learnability of noun class systems in three input conditions: no agreement, alliterative agreement, and non-alliterative agreement. We found that participants who learned the non-alliterative agreement were better at generalizing the noun class system to novel nouns with the relevant semantic features. There was no difference between the alliterative and the no-agreement conditions, suggesting that the possible learnability advantage of agreement marking lies in having distinct forms as cues