Breakdown of Älä sano vuorosanaa ilman kirjaa!
kirja
book
sanoa
to say
älä
don't (negative imperative)
vuorosana
the line
Questions & Answers about Älä sano vuorosanaa ilman kirjaa!
Why is the word for "book" in the partitive case (kirjaa) instead of the basic form?
This is because of the word ilman (without). ilman is a preposition that requires the noun following it to be in the partitive case. So, the basic word kirja takes the partitive ending to become kirjaa.
I thought Finnish mostly used postpositions. Why does ilman come before the noun?
You are right that Finnish relies heavily on postpositions (where the location word comes after the noun, like in talon edessä), but ilman is one of the few true prepositions in Finnish. It usually comes right before the noun it modifies, just like in English.
Why is the object vuorosanaa also in the partitive case here?
Because this is a negative sentence. Whenever you have a negative verb or a negative command like Älä sano (Do not say), the direct object of that action must be in the partitive case.
Why is the verb just sano instead of sanot or sanoo?
This is a negative command. To tell a single person not to do something, you use Älä followed by the verb stem without any personal endings. For the verb sanoa (to say), that basic stem is sano.