Well, the Skerg from SF 1 aren't talking so differently from Urgi. If you have played The Breath of Winter there are different Skerg-NPCs talking like that (Willit, Hulu, Skerg Healer). So it is logical to go on like that.
Furthermore - Urgi is much older than any Norcaine Slave because he already served the Shapers.
And the Norcaine slaves also only spoke in half sentences "Yes Master", "Immediately Master" ...
So I think it's allright to let him speak like that. And if you want to have a creature scrambling up the language it always will sound like master Yoda
So may force be with you