Interview Questions

On Monday I will be helping to interview two applicants for a Software Developer position in my organization. It is important to me that the person selected has great communication skills because in my role I will be communicating with them frequently. I am basically the spokesperson for the application that they will be developing and it is my responsibility to filter and prioritize all feature requests and enhancements, so it is important that we can work well together. I am also solely responsible for the training of this software application which also requires a lot of communication with the developers.

Does anybody have suggestions for interview questions that can help me evaluate whether they will fit the requirements described above? There will be other interviewers slamming the applicants with tech questions so I would like to focus more on soft skills such as communication.

Not totally training related but I am sure you will have some good advice. Thanks.