Changing Register

In Finnish, the boundary between standard language (yleiskieli) and spoken language (puhekieli) is a spectrum rather than a strict binary. Speakers frequently mix features depending on formality, audience, and emphasis.

1. Formal Register (Yleiskieli/Kirjakieli):
Used in news broadcasts, official documents, books, and formal speeches. It follows the strict rules of standard verb endings and full pronoun forms like minä, sinä, and he.

2. Casual Register (Puhekieli):
Used in daily conversations, text messages, and social media. Key features include:

• Pronoun changes: Spoken pronouns are used: minä becomes mä, and sinä becomes sä. For third-person pronouns, se and ne commonly refer to humans as well as things, alongside regionally and situationally varying use of hän and he. The pronouns me and te remain identical to their standard forms in the nominative case, but their declined forms often change (e.g., meidän becomes meiän).
• Pronoun retention: While standard Finnish often drops 1st and 2nd person pronouns (pro-drop), spoken Finnish typically retains them (e.g., using mä oon instead of just olen).
• Demonstrative shifts: While tämä and tuo remain demonstratives, their forms shift to tää and toi in casual speech.
• Verb changes: The 1st person plural uses the passive form (me mennään). In a widespread colloquial 3rd-person plural pattern, verbs take the 3rd person singular form (e.g., he menevät becomes ne menee, he puhuvat becomes ne puhuu, and ovat becomes on).
• Common verb contractions: Frequently used verbs are shortened, such as olla, mennä, and tulla becoming oon, meen, and tuun. In the negative, ole becomes oo (e.g., en ole becomes en oo, et ole becomes et oo).
• Conditional shortening: The conditional marker is often shortened by dropping the final vowel (e.g., olisi becomes olis).
• Possessive suffixes: Possessive suffixes are typically dropped, relying only on the genitive pronoun (e.g., mun kirja instead of kirjani).
• Phonological shifts: Vowel sequences are often contracted (e.g., mäkeä becomes mäkee). The 'd' sound is also frequently dropped or changed (e.g., tehdä becomes tehä).
• Shortening words: Sounds or syllables are often dropped in common words (mutta becomes mut, sitten becomes sit, että becomes et, and niin becomes nii) and in case endings (e.g., -sta becomes -st, -lla becomes -l).
• Numerals: Numbers are frequently shortened (e.g., yksi becomes yks, kaksi becomes kaks).
• Postpositions: The common postposition kanssa is shortened to kaa (e.g., mun kaa).
• Question clitic shortening: The question clitics -ko/-kö are often shortened or modified (e.g., tuletko becomes tuutko, tuuks, or tuuksä).

3. Strategic Mixing:
Native speakers often shift registers within a single conversation. For example, a person might use casual Finnish to tell a story but shift to standard Finnish to quote a law or a formal rule to add authority to their words.

More Common Reductions
The plural demonstratives nämä and nuo often appear as nää and noi. Past participles can lose final t: tehnyt → tehny, mennyt → menny. Compare standard En ole tehnyt tätä with colloquial En oo tehny tätä. These are common correspondences, not a rule requiring every speaker to shorten every word.