To Cheryl or anyone else with a non-verbal child

Cheryl,
Tristan is non-verbal. Naturally, we started out with a PECs book with fairly large icons and added as he increased his vocabulary. When he outgrew the book , getting cumbersome and tattered from use, we added CheapTalk (an augmentative device of which there are many). The icons are much smaller and it took a little time for him to acclimate himself to 1. the smaller icons and 2. the voice that transmitted from it (we asked a boy in second grade to provide the voice instead of his brother because Tristan would find that even more distracting). We encouraged the use of sign when he was starting out in early intervention as another outlet of communication and he half-heartedly used it but over the last few weeks we have noticed a huge increase in his use of it in his receptive language and I think that is because it is more convenient for him to use sign that the CheapTalk when responding to a question. Both my husband and I are trained in American Sign because back then, 3 years ago, we thought that he would be using sign more than any other alternative. His concern is that Tristan does not live in a deaf community and most other people beside our immediate family and school staff do not uses sign therefor we should encourage him to use CheapTalk. My feeling is,and his teacher and aides agree,that if he is more comfortable using sign and back it up with an attempt at verbalizing the word then that is what is most important. I think he is afraid that no one else will understand him but us. I understand his concern but he has increased his vocabulary tremendously using sign.
I would be interested in your feelings about this. Sorry about all the run-on sentences! It got a little wordy!