Apartments are easy to come by. You can get a nice one for ~400-600€ a month, probably even a small house with a garden in some spots.

Most of the younger generation (30 or less) will speak decent English, older people will be mixed. Porto has been getting touristic lately though so most public places should be used to it. We don't dub movies so we tend to have a bit more exposure to the language than most (plus you can go to the movies).