My dh only speaks Spanish (native Spanish speaker) and I speak English. Thus, the boys get more English than Spanish. Ds6 loves Spanish and using Spanish in non- English settings. He now can read easy readers in Spanish.
He did struggle as a toddler, saying some words only English, some only Spanish. By 2.5, he knew to speak English to English speakers and vice versa.
My ds 3.5, refuses to speak Spanish, but understands everything.
I do think a fun person with songs and activities will help. Also, lots of exposure will help too. Give it a try, and see how your dc reacts.
