Accidentally changed Language in User options can cause an issue with logging in to the configuration if you have not the appropriate licence for the language. In this case you might see something alike the following.
The simplest way to fix it is to change the language in User options but if you have no administrator rights or the administrator is yourself... In this case you should use Microsoft Dynamics AX Configuration Utility
Set Configuration command to run at kernel startup parameter to the value, i.g.,
or another correctly licenced language.
It will override the value chosen in the user option and the configuration then works.
Now, you are allowed to say to the system - Speak My Language!