Questions & Answers about Sohvat laitetaan salissa seläkkäin.
How is the word seläkkäin formed from the word for 'back' (selkä)?
The suffix -kkain/-kkäin means 'mutually' or 'in relation to each other'. To attach it to selkä (back), the word goes through consonant gradation: the strong lk changes to a weak l, changing the stem to selä-. Because of vowel harmony (the front vowels e and ä), we use the -kkäin version of the suffix. So, selkä + -kkäin becomes seläkkäin (back to back).
Since the sofas are the object being placed, why is sohvat in the basic plural form instead of the partitive?
In a passive sentence like this one (laitetaan), a plural object takes the nominative plural form (the basic form ending in -t), rather than the partitive plural. The whole group of sofas is being placed, so it acts as a total object.
Does sali mean 'hall' as in a hallway or corridor?
No, sali usually refers to a large, open room, like a hall in a manor, a gym (kuntosali), or a dining hall. If you mean a narrow hallway or corridor in a regular house, you would use käytävä or eteinen (entryway).
laitetaan is the passive form. Could this sentence also mean 'We place the sofas...'?