Jasmine,
YOu said your son 未講野? What do u mean? Dont like to speak or just can say some single word? 如前者, 不用怕, 只是 shy. 遲些會好. 如後者, 有沒有給健康院知道?
In your case, I think you may need to choose playgroup rather than any summer courses.
Causeway Bay ok? => http://www.youngtalents.com.hk/
My daughter took playgroup here before went to N1. The contents there is ok, close to what would done in kindergarten.
We also tried Baby Dynamites at Causeway Bay when she is one yrs old. So far so good.