Sweden is a rather attractive country to work in. The tax is high but most other things are really good. If you are planning to move to Sweden it may be a good idea to lear the language. Non Swedes that work in Sweden can get by using english. Most professionals in Sweden are good at english. Learning the native language is not necessary but of course better during the part of life that doesn't involve work.
Many of my co-workers, both close and at a distance, are from other countries. Within the academic world we can expect many nationalities and many languages. To be able to work in groups and as a whole department there has to be a common language. Either english or swedish. Since you probably need to use swedish outside of work this might be the best solution.
It is possible to take lots of different courses to learn swedish. The best alternative though is problably to learn swedish online. You can take the lessons in your own time and tempo, and in the end of the each course do a test to check how well you have learned. This kind of course will cost you some but the advantages are many.
The alternatives are for example to take a course at the closest university. You learn the basics of the swedish language but it may still be hard to learn how to speak. Even if the university courses are free, you don't have to pay anything, you can't expect to be admited. The number of course members are limited. So there are some obvious limitations when it comes to university courses.
Even if you know a language you still have to learn what kind of activities Swedes often are involved in and the social rules for thoose activities. It is part of the culture. So you also need to learn the Swedish culture to take part in the society.
Some examples of what you can do is learn the concept of and activity "fika". You can also take part in a quiz nigth at a lokal pub. Swedes often excercise and spend time outdoors. Swedes are also fond of music in many forms. Look this up and try to find other activities to do while you live in sweden.
Good luck in finding a course to learn the swedish language and to have a good time while staying here.