Hi Winnie, not to worry about your child speech issues it won't affect. My aunt daughter also the same, she was drooling excessively too when she was 20months. But it didn't affect her speech. If you're worry then you may want to seek a 2nd opinion. My mother in law told my aunt to go other ppl place and use their cloth to wipe her mouth and throw away the cloth, then she try. After a week, her daughter stop drooling . You can give it a try too if you want. It's all those older generation teaching.