Hi Aurelie,
I am not sure if it is a problem of the language why I can't get my version of your survey displayed on the Survey123 website (I get a BAD REQUEST warning but can't tell why…).
I get all entries and fields shown in English though when opening the feature service in AGOL. Is that also the case for you?
In the excel file you provided, the default language was set to Khmer which I changed to English (en). I can still switch between the languages. I removed furthermore the extra column label and kept only label :: Khmer (km) and label::English (en) - I am not sure if it makes a difference if you put the label name actually in Khmer characters.
Would it be possible for you to let me access the stakeholder view in Survey123 to see if it opens for me? (nicueber@esri_rw)
I invited you to our Testing group so you could see if my feature service looks the same as yours. I am not sure if you can see the survey itself too, I also shared the form service.