Re: THEORY: Tonogenesis

£ukasz,

I've been doing a lot of research on tones for my Bauhinese language
and I've compiled quite a few notes on tones for East Asian
languages.  Alas, I haven't had too much opportunity to digest them
yet, but I can share a few things:

On Proto-Tibeto-Burman:

"The conditioning factors that led to the development of tones can
be shown to have been voiced-voiceless contrast in initial and final
consonants and consonant clusters. Because the conditioning factors
were involved with morphological process (affixation and consonant
alternation), tonal systems could also acquire certain grammatical
or structural functions. An independent morphological system
involved or resulted in vowel alternation."

"The sound system of Proto-Karenic appears closely related to that
of Proto-Tibeto-Burman. The tonal classes can be reduced to two,
which connect Karen to Burmic, Sinitic, Tai, and Miao-Yao."

On Tibetan:

"Most Central languages and dialects, including Lhasa, have lost all
consonant clusters and final stops and in the process have acquired
a larger inventory of single consonants and a system of tones."

"The tones of the remaining Tibetan dialects can be accounted for by
positing an original and older system of voiced and voiceless
initial sounds that eventually resulted in tones."

On Burmese:

"The tonal system of Burmese (unlike that of Tibetan) developed to
compensate for the loss of final features."

On Sinitic:

"Sinitic tonal systems can be reduced to two basic tones ultimately
probably accounted for by different syllabic endings."

"What can be reconstructed for Proto-Sino-Tibetan are a set of
conditioning factors (as, for example, certain syllabic endings)
that resulted in tones; the tones themselves cannot be
reconstructed."

Hopefully some of that was of interest.  And yes, it was lifted
shamelessly from the Encyclopaedia Britannica.  The main branch of
the Bibliotheque Municipale is closed for the summer, and they have
all the good language books.

Someone on the East Asian Conlangs group on Yahoo might also be able
to help you.  They've helped me with my Bauhinese tones.

Cheers,
Eamon