Hello! I'm trying to raise my kids (3 yo girl, 5 mo boy) bilingual, as I was raised the same.
My parents both speak Thai and growing up my grandmother lived with us (who didn't speak English) so we had a 'speak only Thai when home' rule. My sisters and I spoke English to each other as much as we could but at home to our parents and elders it was always Thai. We also went to Thai Sunday school so we learned how to read and write.
I speak Thai to my children but my husband does not speak the language. He knows a few words at best but it being a tonal language, it is difficult for him to learn the proper pronunciation. So he speaks English to the children, I speak Thai to the children and he and I speak English to one another.
I've spoken Thai with them since when they were in utero. My daughter went to daycare when I returned to work at 3 months, so her exposure to the mother's tongue was in the mornings, in the evenings and on the weekends. She understands everything I say but doesn't always respond back to me. If I give her the choice between two things (in Thai), she'll choose with the Thai phrase. But she rarely responds to an open ended question in Thai. We recently hired a Thai nanny to help out in the evenings and we've noticed a slight improvement in willingness and/or ability to speak in Thai. I think it's because she sees that its more than just mommy speaking.
When I ask her to speak Thai to me, she sometimes asks me to tell her how and she'll repeat but she doesn't seem to come with stuff on her own. Is it possible for me to get her to speak Thai more? Am I too late?