I'm able to set either everything Finnish or everything English. I want to have Finnish keyboard layout, but the OS language in English. How to do this? In the previous releases I didn't have to do anything.
How to keep the system language in English
First, go to System Settings → Language Support and in Langage tab, apply system wide English:
In Regional Formats apply system wide your favorite English:
Second, go to System Settings → User Accounts and select English as your language:
How to change keyboard layout to Finnish
Go to System Settings → Text Entry and add Finnish keyboard layout:
See also: Language problem in Ubuntu 13.10
But if you are going to make a brand new installation of Ubuntu, there is a step in the installation process (Nº 10 in this answer) where it asks you to set your keyboard layout.