For only two weeks' reading, Edgard, you're doing remarkably well!
You'll have seen from the postings that there is still some debate about the
laryngeals, and some people, on either side, are passionate about their
belief. The consensus, as far as I understand it, is that laryngeals can be
reconstructed before so many initial vowels, that it's probable there were
no initial vowels in PIE.
You show a reconstruction of the verb to be, and speak of the "loss of -e-
on the
> plural persons on present". This is in fact a regular phenomenon, not
> dependant on the presence of a laryngeal. I note that you rightly show
> the shift in accent in these forms. It isn't that in this verb the "a of
> the present [in Skt] diasppears" - rather it is the regular pattern of
> this type of verb in Sanskrit and PIE in general.
Beekes has been recommended to you. If you get on OK with that, you could
look at Szemerenyi "Introduction to IE linguistics", which is much more
detailed - though anti-laryngeal!
Peter