How do I change the language in FS2004?

Microsoft Flight Simulator 2004 (FS9) has no in-game language selector. Its menus, help and content are tied to the localised edition installed from the discs. To change language reliably, uninstall FS2004 and install an edition produced in the language you want; changing Windows language or swapping one DLL is not a complete conversion.

Can I change FS2004's language without reinstalling?

No standard FS2004 setting, command-line option or fs9.cfg entry changes the interface language. Windows display and regional settings do not replace the simulator's localised resources either.

Some releases may provide a multilingual installer and ask for a language during Setup. If yours does, reinstall and select the required language there. If Setup never offers a choice, the disc set is a single-language edition and you need legitimate installation media for the required localisation. A repair from the original discs will only restore their existing language.

This limitation is specific to FS2004 and similar older releases. Other generations use different methods, covered in our version-by-version Microsoft Flight Simulator language guide.

How do I reinstall FS2004 in a different language?

1. Confirm the new edition: make sure its installer explicitly supports the language you want. Packaging translated into your language does not necessarily mean the software is multilingual.
2. Back up your files: archive your add-on aircraft, scenery, gauges, modules and associated installers. Also copy the Flight Simulator Files folder from Documents or My Documents and %APPDATA%\Microsoft\FS9. Record your Scenery Library order and any controller assignments.
3. Remove the existing installation: uninstall FS2004 through Windows. The uninstaller commonly leaves user-added files behind, so rename the remaining FS2004 programme folder rather than installing over it. Rename the existing %APPDATA%\Microsoft\FS9 folder as well if you want FS2004 to generate a clean configuration.
4. Install into an empty folder: run Setup from the required localised edition, then start FS2004 once before adding anything. Confirm that the opening screen and menus use the expected language.
5. Apply the correct update: if you use the FS2004 9.1 update, use the updater intended for that language edition. An edition or patch mismatch can cause the installer to refuse the update or leave incompatible files.
6. Restore add-ons selectively: reinstall executable add-ons with their own installers where possible. Copy personal aircraft and scenery back in small groups, but do not overwrite fs9.exe, language.dll or other core files with versions from the old installation.

Why does replacing language.dll not change everything?

language.dll is required by FS2004, but it is not a complete language pack. Localised text and material can also be stored in other programme resources, help files, lessons, aircraft documentation and ATC voice files. Mixing files from different editions can produce partially translated menus, incorrect text or a startup failure.

Keep the original DLL and avoid standalone copies from unverified sources. If FS2004 already reports that the file is absent or invalid, follow our dedicated steps for repairing a missing language.dll error rather than using a foreign-language DLL.

Will FS2004 add-ons change language too?

No. Third-party aircraft, panels, gauge labels, manuals and custom sounds remain in the language chosen by their authors. Reinstalling FS2004 changes Microsoft's bundled localisation, not the contents of independently created add-ons.

ATC speech follows the voicepack files actually installed, not an interface setting. If changing spoken ATC is part of the conversion, do not restore the old Sound\ATC folder wholesale. Similarly, restoring the entire old Aircraft folder can put previous-language checklists and reference files back over the new installation.