We've created 2 forms which contain the same questions in 2 different languages. Now, we've realised that in order to have one single database, it would be better to merge both forms, and add a question at the beginning (e.g. "What language would you prefer?") that triggers either language for the subsequent questions.
As we're talking about a rather long form, is it possible to merge them without needing to re-write all the questions one by one?
I don't think, for the use case you describe, merging the forms is the way you want to go. If you're using the HTTP connector to post to script that places the response data into your database, you should just customize the parameter names on the right to match in both connectors, then your script will receive the expected param names.
That being said, you can merge two forms by clicking on the root of one form, clicking the 'add to commonly used elements' on the upper right, and give the template a name.
Then you can go into the second form, and add the template in.