You DON’T need a language certificate, but having one can help !
When it comes to learning a language simply memorizing grammar or conjugation rules won’t be enough. What matters is assessing your ability to communicate.
Speaking is by far the hardest part. It will definitely be required if you want to be able to prove not only your knowledge of a language, but your ability to use it to communicate with other people. Certificates are just pieces of paper. Being able to communicate is all that matters. During a job interview, or while sharpening your interactions with clients or friends - it becomes apparent just how skilled you are in a language.
When I interviewed for companies here in Germany, they appreciated the fact that I had passed a higher level of the German Language Proficiency Test. All my friends who want to work in Germany also have this certificate. So, it can definitely get your foot in the door. Beyond that point though, it's pretty useless.
A certificate cannot prove that you speak...
