['suomi 'on 'helpːo 'kieli 'æːntæː ] - [ˈfɪnɪʃ ɪz ˈiːzi ˈlæŋɡwɪdʒ tʰu̟ː pɹəˈnaʊns] part 1

Suomi on helppo kieli ääntää - Finnish is easy language to pronounce. That's the title of this post in case you are not able to read International Phonetic Alphabet (IPA). I highly recommend you take a look on it ;). Statements on this post refer to Standard Finnish, which is based on the dialect spoken in old Häme Province in central South Finland (nowadays known as regions Kanta-Häme, Päijät-Häme and Pirkanmaa).

Click to see this bigger :D

First of all - the lenght of sound matters in Finnish as it can change the whole meaning of a word! See: lika (dirt) - liika (over-), liikaa (too much); likka (chick); liikka (PE). Vowels and consonants can be either short or long (double vowel & geminate consonant). All vowels can be short or long and so can most of the consonants, leaving only 'd', 'h' (oh well, there's a word 'hihhuli' zealot), 'j' and 'v' out of native letters to Finnish.
For being a Uralic language Finnish still stands out in two respects: loss of fricatives and loss of palatalization. Fricatives are one type of consonants that include /s/, /h/, /ʃ/ or /sh/, /f/, /z/ and /ž/ or /ʒ/ and many others. Finnish has only /s/ and /h/ sounds and all other fricatives are recognized as foreign. Palatalization is typical of Uralic languages, but Finnish has lost it as well. If you're familiar with Russian, you know it's full of palatalization x).

Another interesting thing is Finnish lacks the voiced counterparts of 'p', 'k' and aforementioned 's'. 'B', 'g' and 'z' are included in the official alphabet although not being native to Finnish (they're most likely included because Finland has two official languages, Finnish and Swedish, and because there are new loanwords borrowed to Finnish, like 'banaani', 'gnu' and 'zeniitti'. Letter 'å' is completely Swedish and it's not used in Finnish at all.).

Rest of Latin alphabet letters are also absent. 'C', 'f' 'q', 'w' and 'x' occur only in few loanwords (cd-levy, farao, quebeciläinen, windows 7, xylografia). In addition, in Finland and Sweden the letter 'w' is regarded as an equal to 'v', so it's not often included to countries' alphabets (sometimes it is, sometimes it's not). Instead, Finnish has two letters not in many languages, 'ä' and 'ö' (however, the phonemes are present in them even if not marked with an individual letter, think about 'happy birthday' [häphi böörthdei] ;) )
One sound also found in Finnish, is called äng-äänne (the 'ng' sound). It doesn't have its own letter but it's present in old Finnish words, thus making it part of the Finnish phoneme family. Äng-äänne is marked as [ŋ] in IPA.

• When /ŋ/ is before 'k', it's marked as 'n', kenkä (shoe) ['keŋkæ]. When conjugated, 'nk' can change to 'ng which between vowels is a double sound [ŋŋ]
• Newish loanwords have /ŋ/ elsewhere too, and it can appear even before 'k'. In those cases it's marked either 'ng' or 'g', pingviini (penguin) ['piŋviːni].
  
  EXERCISE: Try to guess by looking the IPA's how these words would be written. 
  ['rɑŋkɑ]>['rɑŋŋɑn]
  ['lɑŋkeɑ]>['lɑŋŋenːut]
  ['iŋresːi]
  ['mɑŋneːtːi]
  ['siŋneːrɑtɑ] 

There's also one HUGE thing "which restricts the occurence of some vowels in some non compound words" as I told on my 1st post. This is vokaalisointu (the vowel harmony).
Vowel harmony is there to preserve the pronunciation as easy as possible. Front vowels in Finnish are 'ä', 'ö', 'y', 'e' and 'i' while back vowels are  'a', 'o' and 'u', based on the location of the tongue in mouth where the sounds are produced. 

X-ray showing person's inner mouth

As you can see, E and I make the harmony :D

To be in 'harmony', front and back vowels aren't supposed to meet. This causes desynchronization. Hovewer, 'i' and 'e' of the front vowels are neutral vowels and can freely join either front or back vowels. One (non-compound) word can have:

• back vowels + neutrals (talo house, malli model, taika magic,)
• front vowels + neutrals (mäyrä badger, Ylöjärvi, äiti mother)
• only neutral vowels (peili mirror, ele gesture, hiili coal) 

 Compound words (words with two or more parts, as of 'lawsuit', 'football'...) are considered having separate words so likes of 'kirjahylly' (bookshelf) and 'säätiedotus' (weather forecast) are not against the rules.
Foreign words not following vowel harmony seem strange to Finns. New loanword olympialaiset and sekundäärinen sound weird as they exhibit vowel disharmony, as does an Estonian placename Pärnu. However, Finnish people tend to apply the vowel harmony by custom and pronounce those as 'olumpialaiset', 'sekundaarinen'.
Vowel harmony is characteristic of some languages, mainly Korean (loosely though), Turkic languages (Tatar, Turkish, Kyrgyz and Kazakh), Yokuts, Sumerian and Uralic languages which include Finnish and Hungarian (oddly, Estonian has lost it, though the non-neutral front vowels occur only in the first syllable).   

That's for now. Till the next time :D