The question is not complete, but I will be explaining one or two things here so that you will be able to tackle a similar question.
Explanation:
According to researches conducted by neuroscientists, it has been observed that children process language since birth( even since when they are in the womb).
According to the question, Christopher is a 5-month-old American and he is exposed solely to English language. If Christopher hears another different language, he would know that the new language is different what the normal(English) that he has been listening to for some times. Christopher would have been processing the information of the English language, so he will be able to know that he is now listening to a different language. Infants have some kind of ''phonetic stimuli' controlled by the Brain.
CONCLUSION: INFANTS ARE ABLE TO DIFFERENTIATE SOUNDS OF ANY LANGUAGE.
It is because of China had multi party elections an opposite party and a press free to criticize the government then so many people may not have died in the famine.
