Thanks for all the helpful replies. I will invite the nephew to Mary Heiny's kid's class w/o interpreter and see how he does; actually I have approached the regular kid's teacher about having him train Saturdays, no interpreter--his own teacher suggested it. I guess I'm just a little concerned about him missing something because most of the classes I attend are *very* verbal. You're right about congenitally Deaf people's visual skills---they are developed to a much higher degree than ours (see "Seeing Voices" by neurologist Oliver Sacks). The nature of signlanguage---a language of subtle motion in three dimensions (four, if you count time), develops nerve traces in the visual cortex most of us just don't have. This is a definite plus in martial arts training.
BTW, for info on the upcoming Mary Heiny seminar we're hosting, see <www.twocranesaikido.com> It's probably on AikiWeb, too. Bye