Germanic
From Arsmagica
At the dawn of the 13th century, inhabitants of Scandinavia speak the Old Norse language. This is split into three dialects: Old Gutnish is only spoken on Gotland (a Swedish island), while Old West Norse and Old East Norse cover the vast majority of Scandinavia. All the dialects retain mutual intelligibility, and are less different from each other than the Irish spoken by a Connachtman and the Irish spoken by an Ulsterman. A good analogy is to compare Old West and Old East Norse, to the English spoken by Americans in different parts of the country. (Do you "pahk the cah" or "park the car"? Do you drink "pop" or "soda"?) Old West Norse and Old East Norse are the same language-- the only differences are in the accents, the style of writing, and a few regional slang terms.
Wikipedia had a great map showing the general distribution of the dialects:
Red is Old West Norse; orange is Old East Norse. Pink is Old Gutnish. Blue is Crimean Gothic. Green areas are those whose native languages retain a significant degree of mutual intelligibility with Old Norse. Most interesting is that Middle English is mutually intelligible with Old Norse. I guess I should have expected that, seeing as how Middle English started IN 1066, but sometimes I can be painfully oblivious to the obvious.
Old Norse also shows a high degree of mutual intelligibility with the Q-Celt family (Scottish Gaelic, Manx, and Irish Gaelic). I find this particularly interesting, because I wonder who was kicking whose asses and who stole whose words. Historians and linguists today can make a better case for it being the Vikings who brought Norse words to Scotland, but that's because the Norse wrote things down very early on, while MY ancestors were too distracted by the consequences of dangling their testicles in sub-zero weather to invent parchment or vellum.
Old West Norse is the "proper" language of all Scandinavia (think RP English), but Old East Norse is more common.
Circa 1200 AD, most of Denmark speaks Old East Norse, though there are Old West speakers around as well. Due to the influence of the Hanseatic League, however, it is not uncommon for those in the coastal regions of Scandinavia to have learned to speak Middle Low German. If you're a merchant anywhere in the North or Baltic Seas, you have taken the time to learn Middle Low German.
Old Norse will remain the language of the entire area until the mid 14th century, when the Black Death wipes out half the Scandinavian population. After ~1350, we will see the divergence of distinctive (yet still mutually intelligible) Swedish, Norwegian, Danish, and Icelandic languages. The surviving 14th century texts of these languages can still be read and understood by modern speakers of the languages (my Swedish friend Sophie can read the Gutasaga, if that tells you anything).
http://www.ling.upenn.edu/~kurisuto/germanic/language_resources.html has some texts and glossaries from different Germanic languages. There's a good Gothic glossary in there, as well. As best I can tell from looking up some common verbs and nouns in Gothic and different German languages, it's clear that all the middle Germanic languages take their roots from the Gothic language, but the Gothic is so quaint and archaic that it should be unintelligible to a German when spoken. (So when Leona speaks Gothic to a Norseman, it's about as understandable as Middle English would be to a present-day American-- or like Classical Latin being spoken to a present-day Italian. You might be able to piece together the majority of meaning from the written word, but the spoken word sounds totally alien. The only people in Mythic Europe who can understand Gothic are some mystery cultists in House Bjornaer, and some people in the Ukraine.)
I would argue for the following game rules based on this information:
- Treat Old Norse as one language. If a character wishes to be proficient in all regional accents, have a 6 in it, but your native dialect would be your specialty. If not a native language, but a learned one, then the specialty would be determined by how you learned it-- if learned in an academic setting, your specialty would be Old West Norse. If you learned it by experience, the specialty would be determined by where you learned it.
- The languages of the British Isles should be split up into abilities based on the family. Goidelic languages (the Gaelic family) would be one ability, and the Brythonic languages (Cornish, Welsh, etc) would be another. Middle English is its own ability, as is the Norman French spoken by the nobility.
- Mutual Intelligibility: Old Norse can be understood by speakers of Middle Low German, and Middle English. Treat language skill as two less when conversing between Old Norse and the other two. Both Middle Low German and Middle English derived from Old Saxon, so these two languages should interact in the same way, as well. The Goidelic family has been heavily influenced by Viking invaders, and thus should be also intelligible with Old Norse at language ability -2. (P-Celt, Q-Celt, and Middle English share no mutual intelligibility among each other.)
- If you're a merchant or Redcap anywhere in the North Sea, Baltic Sea, or anywhere in Northern Europe, you damn well better have put a lot of points into Middle Low German. If you're relying on mutual intelligibility to get by, then business is very, VERY bad for you.