How can I help to increase the vocabulary of my child in English?
I've been reading many articles related to multilingual child in this website. I would like to post our situation and seek some advises.
We are a trilingual family living in a 4th country. I and my husband has totally different mother tongues and we communicate in English. We are relatively fluent in English but our vocabulary is quite limited. Our son was born in US and lived there till he was about 3. We noticed that he learned many words that we didn't know at that time already. Then we moved to a 4th country about 2 years ago. So now our child speaks 4 languages. We notice that he still gets some new English words from time to time, but much slower than before. Concerning that he feels most comfortable to speak English and it is also our family communication language, I really would like to keep it up as (one of) his mother tongue. So I have 2 questions: 1) How many language can a person master at the level of mother tongue? 2) How to help him to increase his vocabulary pool?
Thanks a lot!