Frisian                 Frysk

Classification: Indo-European; Germanic
Number of speakers: 300,000
Frisian, or more precisely West Frisian, is spoken in the Netherlands, in the northern province of Friesland, including the West Frisian Islands. Another dialect, North Frisian, is spoken in the northern German province of Schleswig-Holstein, which borders Denmark, and on the North Frisian Islands to the West. The numbers below are in West Frisian.
In many ways, Frisian is the most closely related language to English. Some linguists believe that Old English and Old Frisian descended from a common ancestor, called Anglo-Frisian. There's a simple rhyme that's more or less mutually intelligible in both languages: "Good butter and good cheese is good English and good Frys." In Frisian that's "Goed bûter en goed tsiis is goed Ingelsk en goed Frysk."

Frisian

Source for numbers: http://www.travlang.com/languages/