[rmlew]

The Scandinavian branch of the Germanic languages is missing Skansk, the dialect of the Skane (Scania) region of Sweden. I believe that it was a dialect of Danish with Swedish influences. Few people speak authentic Skansk. The term is also used derisively by other Swedes to refer to the Modern Danish and Skansk influences on the Swedish used currently in the region.

Riksmal is now a dialect in Norway. Most people speak varients with Danish and Swedish influences like the official dialects of Boksmal (literary/formal speech) and Nynorsk (New Norwegian).
The list is also missing Ladino (a Jewish dialect of old Spanish) and Yiddish (Jewish High German with Slavic influences)

[SunkenCiv]

Yiddish is on the list in message 20. I didn't make the other lists, but my guess is that quite a number of dialects (hundreds, or thousands, such as Ebonics) aren't on there.