You were an Aussie lad, thick accent, and Aussie attitude, you worked for Makarov until you got shot, Roach had saved you and convinced Price recruit you to TF141, after a while you and Roach had gotten close, he had got Aussie a slight accent. While you and him were training recruits, he heard one recruit, Jason, mock your accent, so in response, he thickened his one accent.

"G'day, I'm Sargent Roach, this is your lieutenant, Kai." He said accent matching yours.