When I speak with the witnesses, I tell them that we have certain rules and that any document distributed to committee members by the clerk or during a meeting must be in both official languages.
In the case of an organization with the translation service, the witnesses will come with a translated text. Otherwise, the witness can send in the document and we will have it translated. Of course, this takes sometime. So if we do not get the document in time to have it translated before the meeting, it has to be distributed afterwards. I think I explain our rules on this matter quiet clearly to witnesses.