Unfortunately, OS 3.9 did not simply extend the OS 3.1 catalogs, but instead populated the catalog in an incompatible way. If you want to continue to use OS 3.9, ensure that the following file comes from an OS 3.9 installation:
LOCALE:Catalogs/
Copy the OS 3.9 catalog on top of the OS 3.1.4 catalog to get a working OS 3.9 GUI back.
While OS 3.1.4. tries to be compatible with OS 3.1 and extended its catalogs in a backwards-compatible way, OS 3.9 unfortunately selected another route and picked incompatible IDs for its translation.
Sorry, but we cannot fix this.