Diagnosis
You have overwritten the language indicator with a blank character, orhave deleted the language indicator. This is not allowed, becausecharacteristic descriptions and maybe headings exist for thecharacteristic.

System Response
The system puts the language indicator back.

Procedure
If you want to delete the language-dependent data for thecharacteristic, choose the Delete function from the Editmenu, or delete all entries made using the language key concerned.