Education is a lifelong process. There are so many things in this world that we don't know about. We should be able to learn about whatever interests us, at whatever stage in life we want! Learning a new language is sometimes a necessity, but even if it isn't, there are a number of good reasons to learn a new language!
Language courses are run by most universities as well as a number of smaller colleges and schools. You can find local courses by doing some research on the internet. English school courses can be found very easily. Many universities run English speaking courses for international students.
No matter what language you wish to learn, it is important to choose your course carefully. Always go for courses that are run by a reputable company or institution. Price is also a factor, as often language courses can be exorbitantly priced.
Depending on which language you want to learn, you can find learning aids and materials that can help you grasp the language better. In case of most languages, practice is important. It is therefore important to create opportunities to listen to and speak the language as much as possible.