Is this an issue?

We have 2 yr old twin girls. They spoke a few words in Russian but understood a lot of the simple Russian words. We picked them up and spoke English to them with a few words of Russian. Being twins, they have their own "twin" language. It has been a year. Our twins speak and understand the following languages: "twin", English, Russian, and Spanish to their . They go to a parochial Pre-K3. They attend ESOL for English and Spanish twice a week. Also, I have Russian friends which only speak to them in Russian. We play "Binlingual Baby", a video tape to teach a language. This one is Russian. Good luck.