Early Comprehension of Verb Number Morphemes in Czech: Evidence for a Pragmatic Account

The category of number is present in many languages of the world. The category encodes whether a linguistic expression refers to one or more referents and it is used primarily with nouns, e. g. car vs. cars. In addition to that, many languages possess various agreement morphemes that mark number information on elements other than nouns, such as adjectives or verbs. One question in language acquisition research is when children master these agreement relationships. This ability demonstrates the knowledge of dependencies between non-adjacent elements within sentences, thus showing mastery of complex linguistic rules. Number marking in verbs is also interesting because it constitutes a part of the verb inflection system, which is challenging for children in a number of languages. The data on the acquisition of number morphology in verbs is relatively limited. Some information is available from studies that examined when children acquire different grammatical morphemes. In English, de Villiers and de Villiers (1973) showed that children achieve 90% accuracy on using the third-person singular morpheme on verbs between the ages of 26 and 46 months. The case of English, however, is somewhat special because the only number-marking verb morpheme is the 3sg. ending -s. Children may acquire agreement marking earlier in languages with richer verb morphology, such as German or Italian. In German, Clahsen (1986) showed that children master the use of the third person singular morpheme by 35 mohnths of age, and its plural counterpart some two months later. Therefore, if there is any difference against English, it is not large. On the other hand, data on Italian show 90% accuracy of third-person singular and plural verb inflections even in children around 28 months of age (Caprin & Guasti, 2009). The mastery of a morpheme in production does not necessarily correspond to the age when children understand the meaning of the morphemes. It has been shown that comprehension precedes production in various areas of language development, such as lexicon (Fenson, Dale, Reznick & Bates, 1994) or syntax (Golinkoff, Hirsh-Pasek, Cauley & Gordon, 1987). It is thus possible that children