Føtisk is a family (time-wise) of West Germanic languages. Ancient Føtisk (Foietisc) was reasonably closely related to Old English and such, and was spoken on the continent somewhere in the Netherlands/north Germany area around AD 700-1000. For arbitrary reasons, around 1000ish they moved to Schleswig-Holstein and were heavily influenced by the neighbouring North Germanic languages. Ideas exist for Old Føtisk (Fœtisk) (1000-1500), Middle Føtisk (Fœtisk) (1500-1800) and Modern Føtisk (unorthographied).
By Middle Føtisk, it's a minority language, and stays that way.
 That's Foetisk if you can't get the oe ligature. (Føtisk is the English name. Why is there an ø in an English name but not in the names of any of the languages? The simple reason is that I was originally going to have it spelt with an ø-macron in Modern Føtisk, and so my introductory post on germaniconlang had it spelt like that. And I got used to it. And then I devised the orthography for Old Føtisk, reconstructed the orthography for Ancient Føtisk (and now think of it solely in terms of AF > OF), decided that Middle Føtisk was spelt the same as Old Føtisk (if it was written at all), because the languages aren't that different, and decided I hadn't decided on how MnF was spelt... The other answer might be that some other language spells it Føtisk, and so that's how it got spelt in English...)
I pronounced it as /f2:tIS/ in my dialect of English. But I guess the normal English borrowing would be one of Foatish (UK) or Faytish (Am) if I understand correctly. I haven't got up to Modern Føtisk do be able to say how it's pronounced in that, but in Ancient Føtisk, it (Foietisc) was pronounced (phonemically!) /f2:tisk/.
The alphabet used throughout the SR is German Black Letters (a.k.a. Gothic Letters). People write cursive in the Sütterlin script. Roman letters and Roman cursive scripts are also taught in school, but are only used in situations where foreigners may need help; coinage, shipnames, flags, train station names, etc.
The area, called the Foethmarsch, was originally an independent peasant republic until the King of Denmark (who was also Duke of Schleswig and Holstein) conquered the area in the early 1600s. It then became a separate Duchy until it was fully integrated into Schleswig in the late 1700s. The King of Scandinavia, however, still styles himself as Duke of Foethmarsch. It covers the same area as North Friesland *here*.
|North Germanic||West Germanic||East Germanic|
|Eastern subgroup||Western subgroup|| Low Germanic|
|Continental-Germanic||Gothic|| Burgundian †|
| East Frisian|
|Low Saxon|| Alemannic|
|Føtisk|| Crimean Gothic|