I have read that normal progression is that sign production develops sooner that sign reception. But, in the real world, if you understand the client, you should be able to put that into the English language without standing there open mouthed. Is it perhaps they take a little longer to process the message than you are used to?
I agree about the lack of socialization. I have learned a lot from being exposed to different people with their different and localized signing.
In my humble opinion, if the terp (myself included) doesnt understand, then should ask the client to clarify or repeat. Its sometimes embarassing but has to be done, thats what I do.....
Still Learning..............