"Drakensang" sounds imho like an old "Bosparano ?) version of the current Aventurian main languages, especially the "Garethi" from the middle-realm capital called Gareth (without the English th, but rather a normal t, I assume).
Especially in pre- "Year Of The Fire" years it was custom in P&P-material to "quote" much older aventurian texts and books, which had then a language that sounded ... I call it "artrificially ancient", because the real life editors behind it (those who were actually writing the material) tried to invent languages and dialects that are supposed to sound ancient - ancient in Aventurian terms, that is.
So, the Word "Drakensang" sounds to me like an ancient, aventurian word, that has been forgotten or so - but which comes nowadays into the minds of the current Aventurians, who are dealing with what happens within the game.
Plus, the word also is the name of a mountain - and mountains normally *always* have some sort of ancient names ...
Tryiing to describe how to spell it - the way I do spell it, as a German - Id's say it's like this :
The part "draken" reminds me of the English word "drake". The difference, though, is, that the German a is not spoken like the English a.
The English a is pronounced like a German ä.
Hence, the a in "Draken" is pronounced like in the English word "dark" or in "darkness" or in the word "part". I think that comes quite close to it. (Although I'm not a native English speaker, of course.)
The e in "Draken" is a short e like in the English verb "(to) enter".
The "Sang" is pronounced in a similar way. The a like in "part", the overall word like in "song". Just replace the o with the a of "dark", I'd say.
I think that fits to it.