He takes his first Barrayaran oath when he is sixteen. The ImpSec officer spends an hour running through a checklist of points, even though he'd already had certify that he'd rigorously understood the supplied documents on what oaths mean to Barrayarans to get even near this far.
The ImpSec officer then says, "with your honor on your soul's breath and your word as your soul, state your name."
And he recites, the way he's been practicing for months, "on my honor, my name's word rests on the soul of Duv Galeni, who was once David Galen but no more."
And it's fascinating to him that that's all he has to do, from a Barrayaran legal perspective, to change his name. Simply swear it so on his soul. But it's not empty ritualistic words, not to them. These are words they usually only say when swearing vassal oaths or getting married.
And the Barrayarans consider the Komarrans to be honorless, so that's the first step. That's what the oath is for. It's for a Komarran to say: I have honor under Barrayaran law. I can swear an oath on my name's word and it will mean everything to me and I will not break it.
"By my word as Galeni, I swear it," is the only answer he has to give for the rest of the session, the only answer that matters.
Because it's not a simple statement of his name. By his soul as breath, he's swearing allegiance to an entire legal system. An entire planet. An entire point of view.
Barrayarans care about your souls more than you do, he thinks, and he swears to himself as David Galen that one day, these oaths will mean as much to him as they do to the Barrayarans.
To other Barrayarans.