The regularity and complexity in morphological and morpho-syntactic acquisition

This study examines the interaction between regularity and complexity in the acquisition of morphology and morpho-syntax in Hebrew nominal inflection. Seventy-eight Hebrewspeaking children, ages 4–8, were tested, using sentence completion tasks, on nine structures from three linguistic systems: singular adjectival agreement, noun pluralization, and plural adjectival agreement. Regularity and complexity emerged as organizing factors across ages: regular structures precede irregular ones, and within each level of regularity, less complex structures were acquired before more complex ones. The findings are discussed within the Dual-Route Model pointing to the difference between rule-governed and memory-based knowledge, while suggesting that the advantage of regularity could be attributed to frequency as well as to the strength of regularity cues in language acquisition, as proposed by Usage-Based models. The advantage of less complex structures over more complex ones is accounted for by the greater cognitive and linguistic effort required to acquire the latter.