Sedaris “Me Talk Pretty One Day”

a) “Sometime me cry alone at night”.
This is an incorrect sentence. The correct sentence is:
“Sometimes I cry alone at night”.
The pronoun “me” is not used correctly in the first sentence, because it depends on the category person, such as first, second and third person and the category number, such as singular and plural. In the second sentence “I” is correct because is used in English language for first person singular.
b) Last year my brother came to the United States to visit me. He knew the basics of the English language. He was able to understand most of the words, but he couldn’t speak fluently. At the time I was teaching him words and explaining their meaning. Because I thought he needs to know more words to be able to form a sentence. But now after I learned about the syntax I think that he had difficulty because he wasn’t familiar with the rules of the grammar. Knowing the system of rules, it will be much easier for him to form a sentence.