Internationalization (i18n) and Localization (L10n) are used to adapt software according to differences in languages, regional differences and target audience.
Internationalization : the process of planning for future localization i.e. making the software design flexible to an extent that it can adjust and adapt to future localization efforts.
Localization : the process of adapting the software to a particular region/country/market (locale).
To test a device for localization, the device or the emulator can be rebooted in a particular locale by using
adb as follows :
setprop persist.sys.locale [BCP-47 language tag];stop;sleep 5;startwhere [BCP-47 language tag] is the language specific code as described here : BCP47 codes
e.g. to check Japanese localization in the app, use the command :
setprop persist.sys.locale ja-JP;stop;sleep 5;start