Here in Sweden most people are comfortable speaking English so if you address them politely in English they will probably be more comfortable and less caught off guard than if they have to decipher phrases in broken Swedish, no matter how well meaning.
Still probably a good idea to learn some words so you can read signs.
Norway is much the same. Not only that, but even if you do manage to be understood in Norwegian, you might find that you don't understand the local dialect at all.
Still probably a good idea to learn some words so you can read signs.