diphthongs

[Jacob Baltuch]

Michael Witzel wrote:

>Yet, we have an incidental case:
>words such as zreSTha are counted a having 3 syllables, in the Rgveda.
>This does not mean that metrics suddenly works here, just for this -e- as
>it does not in deva.
>Rather, we know that zreSTHa  is from the root zrI, from *IIr zriH,
>with laryngeal lengthening short i > I, long i.
>
>Thus, we get:
>         *zraiH-iSTha > zrai'iSTha (with hiatus? or glide, cf.
>jna-p-ayati)          > zreSTha,
>with e in manuscripts & recitation, but still counted as if 3 syllables!
>
>
>At some moment in the *post*-Rgvedic period thus, after the "RSis" who
>still made their verses using zreSTha having 3 syllables, the monophtong e
>developed. (nothing special about that, again in Pali, etc...)

I'm afraid I have been left behind here. Maybe it's only a matter of one
or two smaller steps so I'd be grateful if Michael or anyone else who's
understood what's going on could fill those in. Just to make sure that
there's no ambiguity let us agree to use asterisks on reconstr. in which
*ai/*aai/*au/*aau are used, nothing for transcriptions and [...] for
the phonetics. Thus e/ai/o/au are reflexes (resp.) of *ai/*aai/*au/*aau
and today are pronounced [e:]/[ai]/[o:]/[au].

So, we have in (the written recension/modern recitation of) some Vedic
texts zre3STha 'best', and zre3STha < *zrai'iSTHa < *zraiHiSTha on com-
parative grounds.

The question is: what was the pronunciation of what e3 stands for, at the
time those texts were composed?

If I understand what you're saying, the pluti-ness of the e must be a relic
in the modern recitation of an original [ai'i] pronunciation. But if that's
the case I'm lost. Why couldn't it be the relic of a [e:'i] pronunciation?