The Finnish linguistic situation is to some extent comparable to that of much of the Arabic speaking world, where Classical Arabic is used in official and religious speech and in the literature, whereas colloquial forms of Arabic are used in everyday conversation and in personal letters.
There are two main varieties of Finnish used throughout the country. One is the "standard language" (yleiskieli), and the other is the "spoken language" puhekieli. The standard language is used in formal situations like church sermons, political speeches and newscasts. Its written form, the "book language" (kirjakieli), is used nearly in all of the written texts, not always excluding even the dialogue of common people in popular prose. The term "standard language" does not actually exactly coincide with the term yleiskieli, because the definition is that yleiskieli lacks the everyday colloquial register.
The spoken language, on the other hand, is the main variety of Finnish to be used in popular TV and radio shows, at workplaces and it is sometimes preferred to speaking a dialect in personal communication. Also, the standard language is quite rare in personal letters and in conversations on the Internet, where strict "correctness" is not in force. The differences between the two are comparable to differences between Standard English and some English ethnolect.
The spoken language has mostly developed naturally from earlier forms of Finnish, and spread from main cultural and political centers. The book language, however, has always been a consciously constructed medium for literature. It preserves grammatical patterns that have mostly vanished from the colloquial varieties and, as its main application is writing, it features complex syntactic patterns that are not easy to handle when used in speech. The spoken language develops significantly faster, and the grammatical and phonological simplifications includes also the most common pronouns and suffixes, which sums up to frequent but modest differences. Some sound changes have been left out from the formal language, such as the irregularization of some common verbs by assimilation, e.g. tule- ? tuu-.
Finnish children usually acquire the knowledge of the standard language when educated in school, but many children who read much learn it as their written "first language". Written language certainly still exerts a considerable influence upon the spoken word, due to the fact that illiteracy is nonexistent and that many Finns are avid readers. In fact, it is still not entirely uncommon to meet people who "talk like a book" (puhuvat kirjakieltä), although this habit is perceived as typical of "old elementary school teachers" and somewhat pedantic. More common is the intrusion of typically bookish constructions into a basically colloquial discourse, as a kind of loan or quote from written or formal Finnish. It should also be noted that it is quite common to hear bookish and polished speech on radio or TV, and the constant exposure to such carefully prepared language tends to lead to the adoption of bookish constructions even in everyday language. However, a foreign learner of Finnish who aims to live and work in Finland should try to acquire a grasp of the most common colloquial reductions in speech, because anybody not conversant with the talk of the street would feel somewhat at a loss in a relaxed speech situation, even if s/he were entirely able to understand the formal language of the news media.
The orthography of the informal language follows that of the formal language. However, sometimes sandhi may be transcribed, especially internal sandhi, e.g. menenpä ? menempä. This never takes place in formal language; some people believe that the sandhi should not be even pronounced in formal language.
formal language — colloquial language
he menevät — ne menee "they go" (loss of distinction of animacy)
onko(s) teillä — onks teil(lä) "do you have?" (vowel deletion)
me emme sano — me ei sanota or mei sanota "we don't say" (notice: fusion of me ei transcribed)
(minun) kirjani — mu(?) kirja "my book" (notice: sandhi n+k ? ?k transcribed)
kuusikymmentäviisi — kuus(kyt)viis "sixty-five"
tulen — tuun "I'm coming" (irregular verb)
punainen — punane(n) "red" (unstressed diphthong becomes a very short vowel)
korjannee — kai korjaa "probably will fix"
mentyämme — meiä mentyy "after we had gone" (notice: sandhi nm ? mm transcribed)
Note that there are noticable differences within dialects. These examples are mostly from Helsinki dialect.