for start i think you can do like example below, the rest will automatically add when the page is load in finnish language, and please translate the loaded new phrase on the fi.py file.
e.g.
languages/fi.py
# -*- coding: utf-8 -*-
{
'!langcode!': 'fi',
'!langname!': 'Finnish',
'Application name:': 'Sovelluksen Nimi:',
}
if you want, i think you can add your fi.py to the web2py github, so that another webp2y user that use finnish language can also use the default that already trasnlated.
best regards,
stifan