Language acquisition is a process where the debate between nature (inherited characteristics) and nurture (effects of learning) is prominent. Most psychologists accept that both factors are crucial in the development of language. Human language is distinct because it is more complex, creative, and spontaneous than the communication systems of other animals.

Linguist Noam Chomsky put forth the innate proposition of language development. He argued that children are born with "universal grammar" and possess a critical period during which learning must occur successfully. According to him, language develops like physical maturation; given adequate care, it "just happens to the child" without direct teaching.

On the other hand, Skinner's emphasis on learning explains why infants acquire the specific language they hear and how they add new words to their vocabularies. This perspective highlights the role of environmental interaction and imitation in the process.

Ultimately, Skinner's theory explains vocabulary acquisition, while Chomsky's theory explains the built-in readiness to learn grammar. Children worldwide show a predictable pattern of development, proceeding from almost no use of language to becoming competent users who can communicate their needs, feelings, and thoughts.