I searched for this specific problem, but couldn't find anything.
I set up a Limesurvey with English as the base language and Dutch as the additional language. Texts are provided in both English and Dutch (I'm not using the auto-translate function). I send a link to the English survey (mylimesurveylink ?lang=en  and (mylimesurveylink ?lang= nl), but sometimes responders would click the wrong survey and want to change the language. There's a built-in "Change Language" button at the top of the form. However, if someone clicks it and proceeds with the survey, their responses aren't saved. What I mean is, the participant changes the language from English to Dutch, proceeds with the survey, completes it and receives the "Thank you for your participation" end screen, but then their responses are not logged in the Responses tab of my admin panel. 
I tried this multiple times, from different computers and different starting languages. The problem persists and all data collected after the participant changes the language is simply lost.

Anyone who's had a similar issue? Is there a way to recover those lost responses? They have to be stored somewhere... Or alternatively, to get rid of the "Change Language" button because even when I provide two links, some responders still want to change the language manually from the top of the form and then all of their responses are lost. 

LimeSurvey version and build number ?

Checked with a core theme ?

...check with exported data.

Thank you. Sorry if this is a silly question, but how would I go about doing that? I'm exporting the responses from the Responses Tab and the ones filled in after a language change are not recorded there (it's as if they don't exist, even though I personally tested it, filled and sent them myself).

LimeSurvey Version 3.17.3+190429

wrote:

LimeSurvey Version 3.17.3+190429
 

The version ist from 2019 and might just have a bug.
Perhaps you don't see and export all results, but only a certain language? Sometimes a filter can cause confusion.
If that is not the cause, the first step would be to ensure that your LimeSurvey installation gets updates from time to time.
Then check again.
 

I mean : did you try yourself ?

Create a sample token
Launch survey with this token
Move next, move next
Change language
Submit

See what happen