Helping child speak non local language - eviltoast

My kid [3yrs] speaks the local language with his other parent (separated. 50/50). and English with me (my native language). I speak both and my kid knows this, so I can’t hide it.

He speaks the local language well, but English is a struggle. Comprehension is 100%, but he only speaks random words. He mostly speaks to me in the local language. Where we live, he will learn English in school, so I’m not worried about that.

I’ve tried various things to get him speaking English, but it’s a struggle.

Are there any strategies that might work?