To provide a general introduction to the study of language

development and consider five major topics. 

To answer the question “What is language?”, and present a definition of language that we build on

throughout this text. 

 To discuss differences among speech, hearing, and communication—three aspects of human development and behavior

that are closely related but are nonetheless distinct capacities. 

To address the five major domains of language, a topic we introduce here and discuss

more fully . 

To examine several remarkable features of language.

To describe differences in and disorders of language development—two topics we explore more comprehensively.