If it was difficult for a child to learn 2/3 languages (don’t most of us speak at least 2 languages fluently anyway?) schools would not be teaching kids French, German, Spanish etc. as they do here in the UK. In fact I don’t think I know a single person who speaks only one language. Children are like sponges anyway, they find it pretty easy to pick up languages.. I used to be fluent in 4 European languages (not counting Latin lol) but as I’ve gotten older and I’ve lost practise I only feel really comfortable (ie speaking without having to ‘think’ the words before I speak them out aloud) speaking two. With my own future kids I’d hope they don’t get ‘rusty’ as I’ve done 
My other half is English, my parents are fine with the situation and have given their blessing (we already have a few mixed marriages in our family as well as many many family friends’ kids who have ‘married out’) as are his and his family but my brother isn’t. He’ll often make little digs (and then get his head bitten off by my dad lol) about it. It’s funny cos he’s the sort of person who likes to think he’s a good Muslim but then comes out with stuff that totally contradicts Islamic principles such as the stereotypical view of a lot of desi guys in over here that it’s ok to have relationships but not marry white girls, even if they want to convert. He even came out with a ‘threat’ to my parents once that if they didn’t allow him to marry his other half (who is desi, Bengali, and no, they would never stop us marrying a person anyway, they just wanted him to complete his studies first) he would go out and get a white girl pregnant. It was one of the lowest things I have ever heard but kinda sums up the attitude of a lot of young desi lads in the UK. I blame my Mum a bit for spoiling him and leading him to believe he can get away with saying and acting however he wants with little or no consequences. He’s a doctor so you’d expect him to be a bit more ‘balanced’ and have his head screwed on but unfortunately not..
My fiance and I aren’t getting married till next year and have to admit my mind is in knots already trying to decide even simple things like could/should I wear a western style white or ivory gown for the civil ceremony (and if so how much skin is acceptable to show without giving all the aunties heart attacks lol) and desi for the reception or go desi for both parts.. Altho we’re generally both v.stubborn and want our own way when it comes to wedding prep luckily he’s been really laid-back and open to pretty much anything, he loves checking out all the bridal lehengas and wedding gowns lol but apart from that, the venue, flowers, invitations etc he’s told me to just go ahead and pick what I want 