Two Types of Logical Structure in Child Ianguage

Abstract

In this paper, we investigate the emergence of two types of logical elements in child language, nominal quantifiers and focus particles. Quantifier noun phrases such as those in a sentence like A nurse looks after every child exhibit both the subject wide scope and inverse scope readings which are represented by means of operator-variable structures subject to conditions on binding. The relative scope of quantifiers is determined not only by syntactic structure, but by quantifier type and thematic roles. Focus particles like also and only partition the semantic structure of the sentence into a presupposition and an assertion. They induce bound variable structures by creating a variable in the focus position, resulting in an open sentence. First, we examine the availability of scopedependent interpretations in Mandarin-speaking children, as well as their sensitivity to the scopal effects of quantifier type and thematic hierarchy. Clear theta role effects were found among all age groups, beginning from the fouryear- olds, in accordance with the thematic hierarchy. Children were sensitive to the distinction between mei ("every") and suoyou ("all") in their assignment of inverse scope. Our data can be interpreted as evidence in support of approaches to scope that crucially incorporate quantifier type into the structural representation. Secondly, we explore the use of focus particles in two-to threeyear- old children whose first language is Cantonese, with both additive and restrictive focus signaled by means of preverbal adverbs and sentence final particles. It was found that additive focus particles were not produced before two years of age, but began to be used before three years old. Restrictive focus markers did not begin to be used spontaneously and productively until shortly after 3;0, emerging later than the additive focus markers, confirming the greater complexity of universal quantification relative to existential quantification. The two studies point to the early emergence of logical structures in children's language.