Hi OP,

Congrats on the upcoming baby (babies?).

I have a mostly bilingual two-year-old boy. His Japanese as of late has overtaken his English a bit, but he's still quite proficient in English and knows a lot of words. I also happen to have a PhD in linguistics and learned a lot about language acquisition during my education.

A lot of commenters gave you all the important details. Speaking English to and in front of him is fantastic. I read English books to my son every day--funny enough, he way prefers it when I read a book to him than when his mother does.

Also, we've stuck to mostly entertainment being in English. My son watches a lot of Paw Patrol, which he mostly enjoys in English. My wife started showing him Inai Inai Baa against my wishes but it is what it is.

Just remember that a lot of input is really the key and he/she'll do the rest!