Whitelady,
Charlotte also have limited words not to worry they will get to speak more slowly,
Charlotte will say hello, hi, bye bye, Please,no more, finish, silly, angry, happy, sad, bored, shy, She still using one word but i am not worry, just try to read with him more he will learn after you teach him. Introduce him more books read with him sitting on ur laps.
As i had been doing that with charlotte so now everytime she will take a book and sit on my lap and ask me to read for her. I also use her fingers to point at the words i am reading and now she also will point once i start reading.