Learn Hardcore Finnish: Yksi koira on kotona ja toinen on ulkona. - One dog is at home and the other is outside.

Finnish doesn’t have definite or indefinite articles. Instead, context or a numeral like yksi (“one”) indicates indefiniteness. So yksi koira literally means “one dog,” and there’s no separate word for “a dog.”

What part of speech is yksi here, and why does it come before koira?

yksi is a cardinal numeral (“one”) functioning as a determiner. In Finnish, numerals precede the noun they modify and both appear in the same case (here, nominative) when you’re simply stating “one dog.”

Why do we say toinen instead of repeating koira in the second clause?

toinen is a pronoun meaning “the other” or “the second (one).” It stands in for koira to avoid repetition. So toinen on ulkona means “the other one is outside.”

Could I say toinen koira on ulkona instead of just toinen on ulkona? Is there a difference?

Yes, you can say toinen koira on ulkona (“another/second dog is outside”), but it is more wordy. Using just toinen treats it as a pronoun (“the other one”) because the noun is understood from the first clause.

What case are kotona and ulkona, and why are they used for location?

They are in the essive case (ending in -na/-nä), a common way to form adverbial expressions of state or location:
• kotona = “at home”
• ulkona = “outside”
Although you could say kodissa (inessive case) for “in the home,” kotona is the set expression for “at home.”

Why is the verb on used for location? Can’t we use a different verb?

Finnish uses the verb olla (“to be”) for both existence and location. Here, on is the 3rd-person singular form, so yksi koira on kotona = “one dog is at home.”

Is the word order fixed? Could I say Kotona on yksi koira ja ulkona toinen?

Finnish word order is quite flexible. That alternative is grammatically correct and shifts the focus or emphasis—highlighting “at home” first. The original SVO order (yksi koira on kotona…) is simply the neutral way to state it.