Language is of great importance to human intellectual development. There is a critical period for language learning, and in order to learn language properly, a person must be exposed to a normal language environment from birth, and babies from different countries naturally learn different national languages in different language environments. The infant brain has the ability to differentiate between language stimuli and other stimuli from birth, and babies develop preferentially in the left hemisphere after birth, even before birth. As the brain develops, the cortical structures corresponding to language activity continue to undergo a process of specialization. 0 to 3 years of age is the period of fastest brain development and the most important period for language learning in children. 5 years of age is the peak of language potential development. After the age of 6 to 7, language learning ability declines at an accelerated rate. If children are not exposed to a normal language environment before puberty, their left hemisphere language potential disappears and they will not acquire normal language skills. For example, Kamala, an Indian “wolf child”, was rescued from a wolf’s den at the age of 8 by American pastor Singh, and lived in human society for 10 years, but she could not speak and could only howl and crawl. After the life of a “wolf child”, the damage to their language skills and intelligence is irreversible when they miss the critical period of language.