Hi Tim_VB14,
Thank you for reaching Microsoft Community.
Please try these steps to troubleshoot the issue on your Surface Pro X:
1: Go to Windows Settings > Time & Language > Language
2: Under Preferred languages, please make sure that Belgian is listed and it should be first on the list. Select Add preferred language if not listed.
3: Select Choose an input method to always use as default below
4: On the next page under Override for default input method, change the drop down from the Use language list (recommended) to the Belgian language you preferred.
Hope this helps.