I work in English and French so we’re supposed to use plain English too, but a few do slip through the net, and a few are exacerbated by the language differences.
The worst one for me is the concept of “ownership” being used in place of “being responsible for”. We even have a department called Owners’ Engineering, which just means engineering contract management. I think it’s because “responsable” can be used as a noun in French, meaning the person responsible for something, and no one can be arsed thinking of a better translation than “owner”.
Acroynms on the other hand are rife, and made even worse by the fact that half of them originate in French and are unchanged for UK projects, so you can’t even have a good guess at what they might stand for because you don’t know what language to guess in.