You cannot translate into the master language &

What causes this issue?

The master language is the language which is in the table TADIR for an
object. It is the language in which the object was created.
You can translate from any language, but not into thr master
language.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Error message extract from SAP system. Copyright SAP SE.