Thank you for your question - it introduced me to the idea of "Joik", and since I have admired the Sami for years, my world is a little bit richer for now having heard some of it...
As far as answering goes - I have a Finnish friend that was good enough to reply to your questions, and I include her words below - her perspective is fascinating, and a good addition to material that I could find elsewhere on the net.
"I came across the yoik in research I did on Sami traditions and their
reindeer husbandry. A yoik, as far as I understand it, is not a song
in the way that we would describe or analyze something musically.
There are no rules on notes, intonations,
minor/major/key/sharp/flat/etc. And, one does not sing a yoik, or
create one, but a 'yoik' is an 'identifier'. For instance, in
traditional animal husbandry for the Sami, each reindeer is called by
his/her yoik that the herder sings. The animals come to their yoik
when they hear it. In the same way, a person develops their 'yoik' for
a way to articulate who and what they are in the world. These change
depending on their circumstances, what they experience... and,
importantly, do not contain actual words, just sounds. A Finnish folk
group, The Girls of Angeli, have made the 'yoik' popularized, and it
is for this reason that people somehow equate it to an actual song.
(info on them here:
http://www.answers.com/topic/the-new-voice-of-the-north)
My understanding is that while it can feel and sound like a song, it
should not be understood as such. That would be like calling what
Buddhist singing bowls do exact notes. No, it is more like an aura, an
energy of tonal inflection that paints itself into a representation of
another physical being. A tonal ghost, if you will.
Oh, and not much has been studied on tonal inflection related to
emotion in other cultures that I know of, apart from some interesting
work in psychology on emotion words (linguistics). While the western
mind might associate a minor note to sadness, this does not mean a
non-western mind would do the same. Sami, and their Northern European
counterparts, cannot be classified 'Western' in the way that the
American public can claim it. Culturally, even the Northern countries
are complete different beasts from each other. :) And, 'positive' and
'negative' emotion words are also subjective, based on environment,
meaning, cultural context. A 'negative' word in our culture is exactly
what is helpful and considerate in another."
Hope this helps!