Because I can speak French and Spanish, it seems stupid not to try to teach my toddler grandson to speak at least one of them. I've been looking after him at least one day a week since he was about 14mths old, and in that time I've tried to speak Sp to him for at least a part of the day. (To start with, I was randomly switching between Fr and Sp, but decided that would be confusing for both of us, so opted to concentrate on Spanish!)
So far, I am really pleased with the results - DGS doesn't even say a lot in English yet, but it is increasingly obvious that he understands a lot of Spanish words/sentences that I use regularly. For instance, when I ask him to go find his shoes/coat, off he goes to find them.
I know that a lot of grandparents start out doing what I'm trying to do, but what I really want to know is if any of you have achieved your objective. Is it realistic to think that a child can learn a language to a decent level in this way, when they are only exposed - and not on a daily basis - to one person who speaks it, and who isn't even a native speaker?