After logging in to Socrative, click on your name at the top right corner and click Profile.
In the Demographics header, you can change your country, school/organization, and language settings.
After making your changes, click Save.
If you currently have an activity running in your account, you won't be able to change the language settings. You'll see the message below:
To finish an activity, go to the Results tab in your account and click the Finish button. Check out this guide to help you on how to end an activity.