Do veneers affect bite, speech and sensitivity?

I've been doing so much research and I am ready to start saving for veneers, but I have a few questions. I don't want to get them if they'll affect my bite or speech or if it'll hurt to eat and drink cold/hot things. I also want them to look natural and not bulky/square, and I don't want them blindingly white. I only want 2 on my front teeth but I have a feeling 4 teeth will be pushed on me so it looks more natural. Would 2 be a weird amount?