Quote Originally Posted by Landwalker
There are, linguistically, two "th"s in modern English, although they're represented by the same letters--they are, however, represented as different symbols in IPA and some Scandinavian (and possibly other Germanic/Celtic?) languages. Basically, it boils down to a vocalized "th" (like in the English word "there") and a voiceless "th" (like in the English word "thick"). Which one of these is being used by the Sweboz, or are they both used? Or, a third option, is it simply an aspirated "t"? Mysteries galore...

Cheers.
Those two are pretty damn close anyway. I know Icelandic uses those two (with two different letters actually; ð and þ), and Icelandic is pretty close to Old Norse which again is pretty close proto-Norse which is basically an outrunner of proto-Germanic from (pre)Roman times.
According to http://en.wikipedia.org/wiki/Proto-Germanic_language, Germanic of that time included a "voiceless fricative" þ-th, and a "Voiced fricative" đ-th. But apparently it is still not an academically settled matter how things were originally pronounced.