My So's first language was Puerto rican Spanish. He has a little girl from a previous relationship, (tho I co-parent her & she calls me mama now) he only spoke Spanish to her unless he absolutely had to speak English to her, or she'd hear him speak English to certain people. When he worked she was watched by his Spanish only speaking grandma. So she knew very minimal English. We started dating when she was 2, 6 months later I started watching her full time.
The only Spanish I knew is what I learned from Dora every morning, LoL so when she wanted/needed something she'd ask in Spanish, I'd answer in English, we both would have melt downs after about 1 min of guessing games! LoL We finally came to some sort of mutual understanding that I'd pick her up she'd point where she wanted to go &/or what she wanted. After I found the item I'd repeat what I thought she called it, until she smiled or repeated the word or gave me some sort of clue that was the right word! I'd say the word in Spanish then in English. Finally after 3 months she started using more & more English but would go home & would ask for what she wanted in English. Daddy would say it in Spanish & she'd start to cry like she was defeated poor kid.
LoL It took a full year of tantrums, crying spells, crabby days, Going on talking strike & pointing & grunting for days on end for her to finally get both languages down & to speak the right language @ the right homes..
(to the best of a 3 1/2 year olds ability anyways) Durign the process of tryign tho, one time she didn't talk for 3 days straight, until we decided she could grunt & point but as soon as we knew what she wanted we would not give it to her until she used her words & in the right language! Tough loving but she started talking again within 2 hours, LoL. Now she's almost 5 & she's fluent on both languages & her FAVORITE thing to do is to talk talk talk talk talk!! LoL She is extremely smart & quick witted & is happy & healthy. Stick with it it will take time, my grandparents were dutch American but never taught the kids any so the little bit of dutch my uncles & mom picked up on they didn't pass on to us kids & I regret it to this day! :( So if you can teach your child to be bilingual as early as possible it's totally Worth ALL of the challenges! (Just remember when your frustrated, that your hair WILL grow back! ;)