With Cvent, you can translate Flex [3] and Classic events into several different languages for your registrants. Most of the default fields, such as labels, instructions, error message, and validations, are automatically translated, but can be customized. Certain text that is not automatically translated, such text widgets, registration questions, feedback survey questions, session names, etc, will need to be translated manually.

• First, configure Languages to on in the setup.
  • Create a default invitation list for each language: No
  • Enable Language Detection: Yes
  • Allow invitation list switching based on language: Yes
• Then, add the Language Selector widget to your Flex website. 

Learn to Enable Multi-Language [3]