Let's assume I want to install Debian in English language.

  • Sure, I will select Language: English - English (default) for that.
  • In a next step I can choose my Country, territory or area (to set the correct timezone I guess).
  • In a third step I have to select the so called Locale settings.

But: What do those locale settings affect?

It seems to be language based (e.g. default setting is United States - en_US.UTF-8). But for what? The language was already selected in the very first step?

What do those settings do? Can I combine English language with German locales for example?

Further question: Can I change the local settings from United States - en_US.UTF-8 to any other locales even if the installation has already finished?

1 Answer 1


In most installations, the “Locale settings” screen shouldn’t appear: the value can usually be determined automatically from the language and country selection. The screen is shown in expert mode, or in cases where the locale can’t be determined (e.g. when I install a system in English but located in France).

The value you choose in the third step is used as the default system locale, which determines the default language and locale settings which are used on the system. The locale setting determines the language used, how numbers, dates, times etc. are formatted, the default paper size, how strings are sorted and compared, and a few other behaviours. If you’re not installing in expert mode, the fact that you were asked to choose a locale is surprising — en_US.UTF-8 is the default when you choose English in the first step and the United States in the second. It isn’t possible to combine any language with any locale; if you try to select English and Germany, you’ll be asked to choose among one of the supported locales because en_DE.UTF-8 isn’t supported by default.

As you surmise, the first two steps also determine the initial values for other selections, including the timezone, download mirror, and keyboard layout.

This is documented in the localechooser README.

You can change the locale once the installation has finished. The system-wide default is stored in /etc/environment, and each user can choose a locale too — typically in the login options (if you’re using a graphical login manager), and/or by setting LANG to the appropriate value in their shell’s startup scripts.

  • 1
    This information was very helpful. I think to answer "But: What do those locale settings affect?" directly, this debian wiki gives the information I was looking for. It affects things like the "Convention used for formatting of street or postal addresses", and "Monetary formatting". I never thought about what 'locale' meant nor how it differed from a language, so that wiki helped me understand.
    – aaaaaa
    Jun 18, 2018 at 0:54
  • 2
    Good point @aaaaaa, I’ve added that to the answer as well, thanks. Jun 18, 2018 at 4:43

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