The Special:Export API should [be able to] export data using the canonical namespace names. This way XML export could be directly imported to a wiki installation configured with a different language.
Currently there is additional two steps required:
- Change the target wiki's language to match the source (this step could be eliminated using the suggested fix)
- Import XML data
- Revert the language back to your desired (this step could be eliminated using the suggested fix)
See related issue T159401#3935518 which workarounds this way.