> Doesn't the fact that the starting point is the vowel /a/, thus the
> words may all be 'mots populaires', thus possibly loans, upset that
> neat picture?
[Screams loudly]
The vowel /a/ is the "starting point" because you have deliberately excluded
all other present tense vowels. There are many examples of reduced vowels,
or zero grade *-l.- which produce Latin -ul-.