Creativity is the first and foremost striking feature of human language. It refers to the fact that language provides opportunities for sending messages that have never been sent before and for understanding novel messages. The grammatical rules and the words of a language are finite, but the sentences are infinite. Every speaker uses language creatively. Even a child acquiring his mother tongue can put speech sounds and words into novel combinations to express meanings. This feature is not found in animal communication systems. Talking birds such as parrots can imitate human utterances, but they cannot segment the sounds and the words in the phrases they imitate and putthem in a different sequence.

　 　Results of experiments show that even animals closest in kin to human beings cannot match children in learning and using language. In the 1930s, Winthrop and Luella Kellogg raised their infant son together with an infant chimpanzee named Gua. When the boy could understand I say what I mean and I mean what I say, Gua could understand neither, although it understood some words. Several decades later, another chimpanzee, named Nim Chimsky (after the famous American linguist Noam Chomsky, who states that language is unique to human beings) was taught American Sign Language, under careful experimental conditions, including record keeping and video taping. After analyzing the video tapes of Nim's conversations, the researchers found that only 12% of Nim's utterances were spontaneous, and of the 88% where the teacher initiated signing, half of Nim's responses were imitations of the teacher's utterance. Children initiate conversations more and more frequently as they grow older. Children hardly ever imitate in conversation. Children become increasingly creative in their language use, but Nim and other chimpanzees in similar experiments showed almost no tendency toward such creativity (Fromkin and Rodman, 1998). Facts like these seem to suggest that creativity is a feature that distinguishes human language from communication systems of other creatures.