On previously Mac OS X version is was possible to change a single application to a different language via Terminal using a freeware application (Language Switcher and App Language Chooser), but I can't seem to get it to work on Sierra anymore.

  • If this is only temporary you can launch the app via terminal like some.app/Contents/MacOS/executable -AppleLanguages '(en)'. – Mateusz Szlosek Jun 9 '17 at 16:34

One way to do this is to go into the app (control click, show package contents, contents, resources) and switch the names of the .lproj files, so that the one corresponding to your OS language actually contains the data for the language you want the app to display in.

This will only work if the application in question is properly localized for the locale you choose. Also, be sure you have a backup copy or plan to reinstall the app in case modifying it breaks anything.

  • This won't work sadly. All the folder are empty so chancing the folder name won't do the trick. I even contacted the developer for a language switch, but that's not in there roadmap.. – Hamkaastosti Feb 27 '17 at 20:07
  • @Hamkaastosti So the app has only been created with one language? That is really unusual these days. – Tom Gewecke Feb 27 '17 at 21:42
  • @TomGewecke isn’t this going to break the codesign? – Mateusz Szlosek Jun 9 '17 at 16:36
  • @MateuszSzlosek I have not heard of anyone having a problem with that so far. – Tom Gewecke Jun 9 '17 at 17:27

Language Switcher works even on Sierra.


  • But it won't work in this case because the app has never been localized in the desired language. – Tom Gewecke Jun 9 '17 at 16:25
  • I can select the desired language in language switcher. But it won't change it.. Its the app 'WhatsApp' – Hamkaastosti Jul 19 '17 at 15:24

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