Ask the classroom teacher to introduce you and what you’ll be doing in the class. When you work with students individually re-introduce yourself. This provides the opportunity to ask for the student’s name and show interest in them as a person by making sure that you’re pronouncing their name correctly. Don’t hesitate to ask them to say their name again or ask how their name is spelled. But don’t describe their name as unusual or difficult to say!
Example: "Hi, I'm ... What's your name? ... Did I pronounce it correctly?"
See this and related tips as a Tip Sheet: http://csteachingtips.org/Tips-for-classroom-volunteers