The relationship between sentence production and comprehension is at the forefront of psycholinguistic research (e.g.Meyer et al., 2016). Psycholinguists are increasingly interested in cross-linguistic perspectives (e.g. Norcliffe et al., 2015).We report studies of the production and comprehension of variable number agreement in Yucatec Maya, an indigenouslanguage of Mexico. We examined the effects of numerosity through a picture description task involving sets of one,two and seven humans or animals depicting an intransitive action. In production more numerous sets led to higher rates ofplural production. In a timed acceptability decision task, number agreement rather than numerosity significantly facilitatedcomprehension. An interaction revealed that plural marking on the noun facilitated the comprehension of singleton versusnon-singleton sets. In contrast, plural marking on the verb facilitated comprehension of large versus small non-singletonsets. These results suggest divergent effects of numerosity in the nominal and verbal domains.

We examine the effects of age and education on the production of variable grammatical morphology among speakers of Yucatec Maya. Our investigation focuses on the use of optional plural morphology when describing pictures of one, two and seven entities performing an action in Yucatec Maya. Our sample (N=69) compares children and adults ranging in age from 5 to 48 years old (mean=19.6, SD=12.1) with levels of education (Spanish-based) ranging from no formal education to some college. Since the use of plural morphology is not optional in Spanish, this is a particularly interesting test of the effects of education in Spanish on sentence production in Yucatec Maya. Mixed effects logit models reveal that set size is a significant predictor of the use of plural morphology and numeral mention. Education, but not age, predicts the use of plural morphology, though only on nouns. We propose a language-internal and language contact-based explanation.