The advanced stage of child language acquisition occurs between late 2 years and mid 3 years. During this stage, children's language grows as their sentence length and complexity increases. They begin to use morphemes, such as present progressive, prepositions, and plural inflections. Children also start to overgeneralize grammar rules, use negative words, form yes/no questions with intonation, and ask some wh- questions. This stage shows significant development in children's syntactic skills and grammar.