- Direct objects and language acquisition by Ana Teresa Pérez-Leroux, Mihaela Pirvulescu, and Yves Roberge
Direct objects and language acquisition, by Ana Teresa Pérez-Leroux, Mihaela Pirvulescu, and Yves Roberge, is a very important book, unavoidable if you are interested in the acquisition of transitivity, direct object pronouns, and Romance languages. At first sight, it appears to be a book on the acquisition of clitics or another piece in the long-standing discussion of clitic omission in Romance languages, but although there is a clear focus on French and Spanish, the book makes important comparisons with English, Italian, Greek, and European Portuguese, and draws on results from several other languages as well. Soon we understand that the book provides a much broader view on the acquisition of direct objects and transitivity.
The book has six chapters and is structured in a way leading the authors from a formulation of the problem—the fact that children may omit objects throughout their development (Ch. 2)—through a description of what this means for the understanding of omission, learnability, and the interaction between modules of grammar (Ch. 1), combined with a thorough review of crosslinguistic differences in the acquisition of objects (Ch. 4). These descriptions and formulations provide the relevant background for a correct understanding of how null objects are interpreted and what it means to acquire a null element, in terms of proper acquisition of lexical, pragmatic, and syntactic features (Chs. 5, 6). Let me go through each chapter in greater detail.
Ch. 1, 'Missing objects in child language', provides a very comprehensive overview of the acquisition of objects in their relation with the lexical properties of verbs. A discussion of the path to learning is offered, with the right balance between innate grammatical features and the role of experience. Besides laying out the research questions, this chapter opens the first major questions: How is transitivity acquired? Why are there missing objects only in some languages? Is this a right description of omission? How do children know about missing objects?
The second chapter, 'From the missing to the invisible', is a key chapter, since evidence is presented against a simplistic binary approach to missing objects. A survey of adult grammars, in particular with data from French and English, reveals that null objects are more common than considered in some analyses and descriptions. In fact, the authors lead the reader to check the availability of null objects of some sort in languages with allegedly obligatory complements. This observation leads to the claim that transitivity is a default and that all apparently missing objects (or invisible, in the case of intransitive verbs) derive from a transitive basis. With this borne in mind, the child's task is no longer to learn when an object is missing, but rather the licensing conditions for the null expression of complements. The consequence of this proposal is very interesting: children are endowed with the ability to have transitive contexts and, in interaction with the inputs, have to pin down the contexts for pronunciation of complements.
In Ch. 3, 'Rome leads to all roads', the actual learning path is explored for several languages. Given the common transitivity basis, it is legitimate to assume that all languages license null complements. However, the input does not confirm this, and the learning child must figure out the exact contexts in which null complements are allowed. The consequence of this is that more-variable inputs slow down the acquisition process, as the child is faced with additional conflicting evidence. This chapter ends with a very interesting point from bilingual acquisition: in a bilingual setting, the amount of input decreases and the degree of variability increases, which explains learning times specific to bilingual children.
The fourth chapter, 'Interpreting the missing object', sets as a goal to refine the learnability perspective developed so far. The discussion of crosslinguistic variation takes into account the uniformity hypothesis from Chomsky (2001...