I see nothing in the Osiris grimoire suggesting he was ever a "speaker in training" though i would be interested to see that info if you can link it to me somewhere and the Proto-Hive [i]males[/i] had a ten year life span but in her own words Taox the sterile mother "lived long" and was chased by the Hive for centuries. And finally the only "Male" thing about the Speaker is their voice so we assume its going to be some Bill Nighy looking old dude underneath but there is nothing confirming the Speaker is a rotating position, or that the speaker is in fact a human/awoken/exo, and to be honest i cant even find anything confirming the Speaker to be male except maybe some in-game dialogue pronouns. It pretty much comes down to the fact that neither one of us can say for sure because we just dont know whats under that mask.