My mother when she arrived in the U.S. after marrying my father didn’t speak very much English. My father wanted very much to perfect his Spanish. After I was born my mother dedicated herself to speaking nothing, but Spanish to me while we were at home alone. At least for a couple years she spoke nothing but Spanish to my father as well. She learned and perfected her English by spending time with his sister-in-law. She knew how lonely my mother was and would come pick her and I up and take us to garage sales.
Having Spanish as a second language helped me greatly in school. It was a help to me when learning to spell even in English. I was able to skip ahead to the more advanced Spanish courses in high school and comp out of them in college. It even helped me to get a job that allowed me to travel the world AND at a much higher rate than they originally had offered for the position (I learned this much later).
It has been rather difficult for me to do the same with my daughter. I have noticed though that she does absorb and understand when I speak to her in Spanish; she knows her body parts, please and thank you and can follow commands. The next step is to get her to converse with me. So, I read to her, sing to her and try to converse with her in Spanish as often as I can. It takes a lot of discipline, though.
My sister-in-law volunteers her time with the deaf community and encouraged me to teach some ASL to my little girl. When she was just 6 months old I taught her the sign for more so she could tell me when she wanted more to eat. Sure enough she picked it up within a week or two. By 8 months she could sign more, thank you and please. My sister-in-law kept saying she was going to teach her more, but I knew that would be too much to ask from such a busy lady. So, I went to the library and got videos and books so that I could learn as well. She learned signs for animals, foods, water, milk, cereal, and others. This actually helped her make the connection with Spanish and English, too.
Once she started talking which was very early the signs kind of went out the window. I still encourage her to sign what she knows so she doesn’t forget. The sign for please is still one she uses frequently.
Even if you don’t know the language try to teach your children. There are synapses that are created with each new piece of information learned. The more synapses we help them create now the easier it will be for them to learn complex information later.