Change the default language in Liferay

You can change default language from Control panel - Portal Settings - Display Settings - Default langiuage. Also you can override params at portal-ext.properties :

#
# Set the default locale used by Liferay. This locale is no longer set at
# the VM level. See LEP-2584.
#
user.country=US
user.language=en

BR, Paul

From Liferay 7 (released in 2016), the default language setting can be found in the UI at:

Control Panel > Instance Settings > Miscellaneous > Display Settings

Don't forget to press "Save" at the bottom of the page.

As MDT said, it overrides whatever is in portal-ext.properties.