Evolutionary Sequence

I figured out something I'd been wondering about this morning. Consider an
isolating language with a CV syllable structure and a typical root length
of three syllables. Over time the following changes happen.

Derivation and inflection by V and CV prefixes and CV suffixes.

Infixation of additional vowels to give CV2V1 as a
derivational/inflectional process.

Derivation/inflection by motion of stress, subject to the following conditions-
1) Primary stress lies on a root syllable.
2) The first syllable always receives at least secondary stress.
3) A suffix is never stressed.

Original vowels merge with or are displaced by infixed vowels.

Loss of (some) unstressed vowels.

And there you have it - a plausible explanation for the origin of the
Semetic morphology!

Pete