Finnish has a reasonably regular structure for the generation of superlatives. You take the adjective X, and add -empi if it is more X, and -in if it is most X.
suuri - large
suurempi - larger
suurin - largest
pieni - small
pienempi - smaller
pienin - smallest
But is it always that regular? Firstly, one of the most common adjectives is almost totally irregular, so you just have to learn it. Here it is:
hyvä - good
parempi - better
paras - best
Then you'll find that a lot of adjectives ending in vowels see the ending vowel change, for example:
paha - bad
pahempi - worse
pahin - worst
Here you loose the ending a on the "most bad" superlative. With the next example we see the first occurrence of the pesky "consonants change" rule - p becomes v:
halpa - cheap
halvempi - cheaper
halvin -cheapest
And with this one the end vowel isn't lost:
iso - big
isompi - bigger
isoin - biggest
So there isn't an easy catch-all rule for superlatives, but they're fairly regular. In fact, they're regularer than English superlatives. Or, to put it another way, Finnish is still ...
helppo - easy
helpompi - easier
helpoin - easiest
