Dora speaks mostly english, so I don't think you'll have that problem unless you want to follow through with it. I don't think she'll learn counting past 5 or 10 anyway, coz Dora doesn't go that far. & by the time she's in school she'll have forgotten most of it, as my girls have.
I think a bit of TV is good for children age 2+. I hate Dora, so it isn't on, but DS adores Thomas (I don't, but can live with it). DS can name different engines, different types of engines, talk about the difference between steam and diesel engines - and makes up stories about them. It's great for him as a base for knowledge and imagination. He recogises numbers and colours from watching Thomas too. I think he may be colour blind, so anything that can help with colours is useful.
I talk in French or Italian (or both, with English thrown in) when cooking, we count and talk in German... DS isn't confused as to the English language. Exposure to languages early is great as it primes the brain to hear sense in other languages when you hear them as adults.
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