Multiple languages are availabe
The Spark Chart user interface is in English, however, surveys can be created in any language. Also, the buttons and messages that appear to survey respondents when completing surveys can be customised.
You can set custom text for the user interface from the Project Settings/Languages tab. This way, you can either present your survey to respondents who don't speak English or simply personalise the experience in their language.
To enable custom labels, select the Yes option to show the text fields you can change.
You can select from pre-installed langauge packages (20+ languages) or customise the fields yourself for any langauge.