The UPD may not have overwritten the dynamic text database. Solution: Start a new campaign. Saved games often retain English strings. If you want to continue an existing save, use a hex editor to force language reload, but starting fresh is easier.
UBOAT - Development blog: Type IX, Flotilla Headquarters, Missions uboatturkceyama upd
The base game has evolved significantly. The new UPD ensures that every new ship type, radio message, and captain’s log entry is accurately translated. Older translation packs often caused crashes or displayed placeholder text like $MISSING_STRING_TURKCE ; the eliminates these errors. The UPD may not have overwritten the dynamic text database
Many Turkish U-BOAT players share updated files in dedicated simulation Discord servers. uboatturkceyama upd