A few days ago, the baby spoke normally, and suddenly he couldn't speak well. For example, the word peanut, he said, what is the relationship between flowers and flowers?

This is a bite. Sometimes children do this when they are young, and so do I when I am 4 or 5 years old. Better be older. In addition, it is also possible that he imitates himself when he hears someone biting his mouth. If this happens, he should be corrected soon. If he gets used to it, he can't change it. For example, teach him to say some simple words or tongue twisters, let him practice more, and tell him not to be nervous when he speaks, and think about it. When he hears himself biting his mouth, he should correct it.