Thanks to a robust education system and lots of bad American television and movies, the majority of Norwegians speak perfectly good English! It’s not hard to communicate both in public and business settings. In most cases they’re happy to switch to English in your presence and sometimes enjoy being able to speak English with you.
That being said learning Norwegian, even in small amounts, can help you build camaraderie with your colleagues. If you plan to stay in Norway for a while there is some expectation in society that you’ll learn the language. Foreigners that stay here for 5+ years can be looked down upon if they have yet to grasp the language so it’s recommended to make some effort in this area. It’s typically always best to show both some admiration and desire to learn the language to your colleagues.
Your pronunciation will likely be dreadful at first and if Norwegians see you struggle they’ll be eager to switch to English for your comfort and theirs. However, if you let them know you’re really trying to learn and appreciate their support it’ll go a long way. It’s important to understand that Norwegians are typically too polite to correct your bad Norwegian. You’ll have to repeatedly ask them to do so, much to their discomfort. In the workplace, you can subtly signal your interest in the language through meetings and everyday interactions. For example, when handing a colleague a coffee or paper say “vær så god” pronounced like vah-sha-go to a native English speaker. You would typically say this after they “takk” (thanks) for giving them something as it loosely means “Here you go.” This is by far the most common opportunity to get started speaking a little Norwegian. You’ll earn a little bump in admiration from your colleagues and they’ll likely be keen to help you learn additional words.