I am just putting this out there. The closest language to English is also by nature the easiest language for native English speakers to learn. I am not talking about Dutch, even though Dutch is closely related to English, and it too is very easy for native English speakers to learn.

No the language that I am talking about is Frisian. This is a language that shares it's roots with English, but over the last 500 years or so it has become heavily influenced by Dutch, and German. (The Frisian islands in the north of the Netherlands).

Frisian: Bûter, brea, en griene tsiis is goed Ingelsk en goed Frysk.

English: Butter, bread, and green cheese is good English and good Fries.

Can you think of any other languages that are closely related to English?