To be - the search for the Gaulish verb (part2)

I was curious about the Gaulish verb "to be", and I tried to work out the present, past and future tenses of it by comparing it to the tenses in Latin, Old Irish, and Welsh. I also started with the Gaulish words: immi, esi, buetid, esti, and biiete.

Being that Latin is the closest in time and relationship to Gaulish, of the three languages, I thought that it would give me some clues about the tenses of Gaulish "to be". Latin didn't help much, though, so I also looked at the verbal endings for the regular verbs in Latin for the present, past and future.

According to the Latin 1 grammar that I consulted "-ba-" indicates past tense, and "-bi-" indicates future tense. I also noticed that the Celtic examples also use the the same fomula, as Latin, in their past and future tenses of the verb "to be".
Example:

• Old Irish ba, bammar, bieid;
• Welsh buost, buoch, byddant;
• Gaulish buetid, and biiete.

According to Christopher Gwinn, biiete translates into "you (plural) all shall be", then maybe "bi-" is the Gaulish future indicator. Buetid was given as meaning "it is", but "esti" also translates into "it is".
I think that buetid means "it was", and that "bu-" is the Gaulish past indicator. Following this logic, these are the forms (*) of the Gaulish verb "to be" that I initially worked out:

After consulting Christopher Gwinn, the corrected present tense forms of Gaulish "to be" are:

"Buetid" appears to be a compound verb. *Bueti + id ("it"). Personal pronouns are sometimes found attached to the third singular forms; probably to help distinguish between masculine, feminine, and neuter genders.

It appears that the present tense of Gaulish follows an irregular form, whereas the past and future tenses follow the regular verbal forms indicated by the two attested examples.

Gaulish *buont has a cognate in Welsh buont. Both words have the same spelling, same tenses, and same meanings; in two P-Celtic languages - one ancient and one modern.
Gaulish *biont shows up in the "Plomb Du Larzac" inscription as biontutu(s).
The suffix "-utu(s)" indicates a subjunctive mood. That means, biontutu(s) translates into "if they will".
The passive voice is formed by adding the suffix "-or". Thus, this produces these forms of the Gaulish verb "to be":

A 3^rd Celtiberian form, robiseti, shows the prefix "ro-". This prefix also appears in Old Irish (roba), and imparts the perfect voice to a verb.
Verb forms without "ro-" indicate a narrative form.

Negative forms are made by adding ne ("not") + the verb.
Example: (Celtiberian) nebintor, (Old Irish) nim.
Interrogative forms are made by adding ne at the end of the verb. Example: (Old Irish) inn.

The 4^th Celtiberian form, cabiseti, shows the prefix "ca-". This prefix also appears in Old Irish (corrabe, corotaicciller). The prefix "ca-" imparts the meaning "until, or so that".
Cabiseti translates into "until you (plural) will".

As a summary I've tabulated the tenses on the next site.

As a summary I've tabulated the tenses here: