【正文】 teeth are unusual pared with those of other animals. They are even in height, and form an unbroken barrier. They are evenly spaced and equalsized, making the articulation of a number of sounds possible and easier. Second, human lips have muscles which are considerably more developed and show more intricate interlacing than those in the lips of other primates and thus provides great favor for the articulation of a number of sounds. Third, human mouth is relatively small, and can be opened and shut rapidly. This makes it simple to pronounce sounds such as P and B, which requires a total stoppage of the airstream. Fourth, human tongue is thick, muscular and mobile which makes the articulation of a range of vowels possible. Fifth, human larynx is much simpler in structure than that of other primates which makes air move more freely through mouth and nose without much difficulty. (Aitchison, 2000: 48) Sixth, the human brainbody weight ratio is much greater than other animals and thus suggests that human brain is different from that of other animals. Further observations depending on patients with aphasia prove that there are certain specific areas in human brain involved in speech planning, prehension and articulation of language (Mackay et al. 1987). Animals Can Never Learn LanguageDuring the past decades, several attempts have been made to teach language to chimpanzees in USA. Not even one chimpanzee could successfully learn language as humans do. Such results and findings suggest that the capacity of acquiring language is innately programmed in human brain.Through continuous observation and exploration into the animal munication systems and human language, linguists have obtained an agreement that language is unique to human and animals cannot naturally talk. But the question whether animals can learn to talk or learn language soon arose, and led to several attempts to teach language to animals. Some birds like parrots can only imitate the sounds or sound strings of human without knowing the meanings, and thus cannot be treated as cases where animals can use language. Therefore, psychologists and linguists turned their attention to apes and chimpanzees who are considered to be the closest relatives of humans. (Aitchson, 2000: 23)In the first several famous attempts to teach language to chimps, the chimps were brought up as human children and were supposed to utter words and sentences. Even though a chimp named Viki did manage to utter four simple words PAPA, MAMA, CUP and UP (Hayes, 1951), none of the chimps in these experiments, strictly speaking, finally could talk in human language. Later technological findings proved that chimps are not physiologically capable of uttering human sounds which justified the failure of the initial attempts. Therefore, later experiments tried to teach sign language to chimps and apes or teach them to press symbols on keyboards instead of directly teaching them to talk.In the experiment conducted by R. Allen Gardner in 1966, a female chimp named Washoe was taught to use modified American Sign Language (ASL) in which signs stand for words. The chimp was kept continuously surrounded by humans who municated with her and each other by signs. Before she grew too large to continue the experiment, Washoe acquired more than one hundred single words, for example, COME, HURRY, SWEET, etc. Her speech showed some design features possessed by human language. First, her speech had semanticity for she had no difficulty in understanding that a sign means a certain object or action. For example, she spontaneously made the sign for flower when she was shown a picture of flowers. Second, she could generalize from one situation to another. For instance, at the beginning, she could merely use the sign for more in the situation to be tickled by researc