The multi-language feature is applicable only to users who have purchased the multi-language license.
First, you need to configure the survey in the various languages you require to send to the end users. This is achieved from Admin -> Define Survey -> Survey Translator -> New Translation. Select the language and define the survey with relevant questions. [ Screenshot ]
So the next time a survey is triggered to an end user, the user will have options to choose the preferred language from the Display Language drop down, after which he can answer the survey according to the language selected. [ Screenshot ]