Frisian is a minority language, with only around ½ million speakers, but I have chosen to include it in this A-Z because it is notable for being the language most closely related to English. English evolved from Old-Frisian, which was spoken by settlers living all along the East coast of England.
It is currently spoken in parts of the Netherlands and parts of Germany. There are three dialects forming Frisian: West Frisian, North Frisian and East Frisian. West Frisian has joint official status with Dutch in the Netherlands. North and East Frisian, on the other hand are not official languages, although they do have protected status in Germany.
If you fancy learning a little Frisian, you’ll find a course on FutureLearn.