A couple of important steps are involved in order to ensure a successful communicative experience across languages and cultures. You’re already on your way to step one: contract a qualified interpreter rather than, say, risk using a family member or other unqualified person.
To the right, you’ll find an American Translators Association (ATA) publication which explains the difference between interpreters and translators and why hiring qualified ones is so darn important.
Below, this brief video from Glendon College illustrates the enormous benefits of working with trained, professional interpreters. At times, lives hinge in the balance.