Having watched a few YouTubers playing this game, it's clear that - aside from the actual Finns - nobody seems to have the first clue about how to pronounce the place-names and other Finnish words in the game. Amusing at first, seriously annoying after a while...
Luckily, it's not all that difficult. Finnish is a phonetically-spelled language, so you mostly just need to learn the alphabet (again). After that, just try to stress the first syllable in each word, rather than the later ones. You'll be sounding like a champion racing driver in no time!
Vowels
There are eight vowel sounds (and eight vowel letters) in Finnish, compared to about twelve vowel sounds in English heaped onto just five-and-a-half letters. This makes it much easier to work out which sounds go with which letters. Doubled vowels are always long, single vowels are always short.
Finnish vowels are grouped into three categories, and you'll never see "front" and "back" vowels in the same word stem. (This doesn't apply to compound words, such as "Rykipohja", which are made of more than one stem.) Each front vowel has a direct counterpart in the back vowels, and I've chosen the example words to reflect that.
Front Vowels
A - as in "heart".
O - as in "bore".
U - as in "food".
Neutral Vowels
E - as in "bet". Take care not to change this sound when lengthening it: English "ee" is spelled "ii" in Finnish. Also make sure to pronounce this even at the end of words, like "Loppe".
I - as in "bit" (short) or "beat" (long).
Back Vowels
Ä - as in "hat".
Ö - as in "serve".
Y - similar to "feud"; exactly like German Ü. This is the only Finnish sound which isn't common in English, but listen to a Scouser say "book".
Consonants
Finnish uses only a few of the consonants in the Latin alphabet, and there is only one surprise for English speakers. Again, doubled letters are lengthened, though this is trickier to master with consonants. The usual advice is either to say the letter twice, or to hold it for a moment before continuing.
G - is always hard G, as in "Golf".
H - is always pronounced separately, and never silent.
J - SURPRISE! As with German, sounds like consonant "Y", so "jet" becomes "yet".
K
L
M
N
P
R - as with H, always pronounce this as a separate sound. Roll it if you can.
S
T
V - occasionally the letter W is also used for this sound, most often with "wanha" which literally means "olde", the normal spelling being "vanha", meaning "old".