You could add a question to the end of the survey that uses JS to switch the language to English.

I have the same issue. And I am not proficient in JS so can't use that option unless i'm spoonfed that solution.

https://community.qualtrics.com/XMcommunity/discussion/comment/47008#Comment_47008This should do it:
Qualtrics.SurveyEngine.addOnReady(function() {
if(jQuery("#Q_lang").val()=="EN") this.clickNextButton();
else jQuery("#Q_lang").val("EN").trigger("change");
});

TomG Thanks! So does this change all values across all questions in the survey to English? Or is there a need to specify by question?

https://community.qualtrics.com/XMcommunity/discussion/comment/47015#Comment_47015I think it will change it across the board. I think any values sent to SF are in the current language at the end of the survey.

Hi Tom,
Thanks for your reply! Where do you recommend to paste the js code?

https://community.qualtrics.com/XMcommunity/discussion/comment/47066#Comment_47066Attach it to a text/graphic question on its own page at the end of the survey.

Hi Tom,
I pasted the code as you recommended; however, I get this loading signs and the page just doesn't load. Any recommendation on what to do?

UPDATE: You may ignore my comment. It all worked. I use British English, hence the code needs to be adjusted to "EN-GB". Thanks a lot for helping out!

Hi @TomG any ideas on how can we send non-english open end comments into english language or a translated comment into Salesforce?

Use a translation API called from a web service.