I believe that late speakers with high IQ have generally a large vocabulary, they can speak but don't dare to speak because they feel they don't master the lang

I believe that late speakers with high IQ have generally a large vocabulary, they can speak but don't dare to speak because they feel they don't master the language. Also I wouldn't call many late speakers have high IQ, on the contrary, the majority would have a lower IQ (or at least on the verbal part when tested at 7). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3139938/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3139938/