They were poets, bards, and to get an idea of those 'mysterious. dark words', read the Edda.
The function was clear in the link I gave: http://en.wikipedia.org/wiki/Skald
and dark and mysterious was not included in the job description.
Not that I don't see 'call' in skald/scald - which is probably more what their name is based in. (Proto-Germanic-sound, voice, shout)
I would have agreed that Kalta's name if meaning call also, was etymologically the same as skald - and skald's definitely were named for their speaking.
The difference is now, you pointed out enough times for me to question it, is that Kalta was named because of her DARK, UNCLEAR words.
Which is why I now consider her name could be from cold rather than call.
And makes sense her name as this description is exact opposite of Minerva, who co-incidently lived on the OPPOSITE side of the Scheldt.