[tied] Re: Indo-European /a/

An althernative view about the origine of the e/o/a group could be as
follows:

1. "a" was the original vowel, perhaps with schwa as an allophoneme.

2. In some cases "a" was preserved, for example in combination with
the laryngeal h2, usually called a-coloring laryngeal, that is: There
was no a-coloring but in fact an a-preservation instead.

3. In other cases "a" was rounded to "o", for example by the laryngeal
h3.

4. In many cases "a" was fronted to "ä" and further narrowed to "e", a
very frequent phenomenon in many languages (English, modern Arabic,
Danish, Vietnamese, tec., etc.)

The qualitative ablaut e/o could originally be an ablaut a/o if it
occured before points 2-3.