On 2008-02-21 21:46, Patrick Ryan wrote:
> Why is it *dwo- rather than *dwé-?
>
> Before endings added.
In theory, it's *dw-e/o-, a thematic stem. The thematic vowel was *e or
*o, the colour being originally determined by the ending -- *o if the
first segment of the ending was voiced, *e otherwise (this original
distribution was often disturbed by analogical levelling, especially in
the declensional system). If *dw-o: comes from *dw-o-X, where *X is the
original animate nom.du. ending, the quality of the thematic vowel
suggests that *X was a voiced or an *o-colouring consonant. As *h3 was
both, it's possible that the anim. nom.du. should be reconstructed as
*dw-o-h3.
All the other dual case forms, animate as well as neuter, had voiced
endings, so the thematic vowel of the numeral 'two' was *-o- across the
board. However, if 'two' occurs as the first member of a compound, we
find the bare stem *dw-V- with the thematic vowel reduced to *-i-, hence
the compositional variant *dwi-.
Piotr