Celtic units names

[Arjos]

There are linguists in the team, who understand Keltic languages far better than me, but what happened was that EB actually used latin spellings, Gaelic/Welsh words, or even faulty grammar...

For example Solduros is correct, but it means "the Solduros" singular, hence it was changed to its plural form Solduroi...

Gaesatae is on the other hand a Latin transcription, afaik it is debated whether it should be (in Gaulish) Gaisates or Gaisatoi...

What looks like hellenised names are the proper o-stem Keltic nouns, one of the declensions in that linguistic family...

While the -i ending, as in Arverni, it is found in later inscriptions, due to the influence of Latin (something not fitting the starting date of 272 BCE)...
Elmetiacos is doind a total overhaul of the linguistics for all the Keltic factions, plus the Leusitane (Lusitani), which will hopefully be featured in the coming release :)