Learn Hardcore Finnish: Tarvitsetko toisen ostoskärryn, vai riittääkö yksi koko perheelle? - Do you need a second shopping cart, or is one enough for the whole family?

After back vowels (a, o, u), you use -ko.
- tarvitset → tarvitsetko
After front vowels (y, ä, ö), you use -kö.
- riittää → riittääkö

So the stem’s vowels decide which version of the question clitic is used.

What does toisen mean, and why is it not just toinen?

Toinen means “second, another, the other”.

In the sentence, you see toisen because it is in the genitive/accusative singular, used here as the object of the verb tarvitsetko:

Tarvitsetko toisen ostoskärryn?
= Do you need a second / another shopping cart?

For a complete, whole object in a normal (positive) sentence, Finnish typically uses the genitive/“accusative” form, which ends in -n:

base form: toinen
genitive/accusative: toisen

So toisen ostoskärryn means “another (one) shopping cart” as a full object.

Why is it ostoskärryn and not ostoskärry?

Ostoskärryn is the genitive singular of ostoskärry (shopping cart).

The whole object phrase is:

toisen ostoskärryn
- toisen = genitive of toinen
- ostoskärryn = genitive of ostoskärry

In Finnish, when you refer to a whole, definite object in a normal positive sentence, the object is usually in the genitive/accusative:

Tarvitsen ostoskärryn. = I need a (whole) shopping cart.
Ostan auton. = I’m buying a car.

So both words in the noun phrase take the same case: toisen ostoskärryn.

Could you also say Tarvitsetko toista ostoskärryä? Would that mean the same thing?

You can say Tarvitsetko toista ostoskärryä?, but the nuance changes:

Tarvitsetko toisen ostoskärryn?
→ Do you need another/one more (whole) shopping cart?
(focus on an additional, complete cart)
Tarvitsetko toista ostoskärryä?
→ More like “Do you (at all) need another shopping cart?”
Here both toista and ostoskärryä are partitive, which often suggests:
- uncertainty
- something not fully defined or not a clearly ‘whole’ object
  or a softer, more tentative question.

Functionally, in a real store situation, both will usually be understood similarly, but grammatically the original toisen ostoskärryn clearly talks about one additional, whole cart.

What is the difference between vai and tai? Why is vai used here?

Both vai and tai translate roughly as “or”, but they are used differently:

vai is used in questions with alternatives, especially yes/no questions:
- Tarvitsetko toisen ostoskärryn, vai riittääkö yksi?
  = Do you need another cart, or is one enough?
It usually implies a choice between the given options.
tai is used in statements and also in questions where the “or” is not presenting neat alternatives (often more like “and/or”):
- Voit ottaa ostoskärryn tai -korin.
  = You can take a shopping cart or a basket (or either).

In this sentence, the speaker is clearly offering two alternative possibilities, so vai is correct.

What does riittääkö mean, and why doesn’t it have a subject pronoun?

Riittääkö comes from the verb riittää = to be enough, to suffice.

riittää = (it) is enough
riittääkö = is (it) enough?

In Finnish, a 3rd person singular verb often doesn’t need an explicit subject pronoun like se (it). The subject is understood from context or appears later in the sentence:

Riittääkö yksi koko perheelle?
Literally: “Is one enough for the whole family?”
Here yksi (one) is the subject of riittääkö.

So:

riittääkö alone already implies “is it enough?”, and
yksi makes clear what is supposed to be enough: one (cart).

Why is it yksi and not yhden here?

Yksi means “one” and in this sentence it is the subject of the verb:

yksi (ostoskärry) = one (shopping cart)
riittääkö yksi (ostoskärry) koko perheelle?
= Is one (cart) enough for the whole family?

As a subject, the default form is nominative, which for yksi is exactly yksi.

Yhden is the genitive (and also used as an object form in some structures), for example:

Tarvitsetko yhden ostoskärryn vai kaksi?
= Do you need one shopping cart or two?

But here, one cart is not an object of a verb; it’s what is enough, so it’s the subject → yksi.

What does koko perheelle mean, and what is the role of the ending -lle?

Koko perheelle breaks down as:

koko = whole, entire
perhe = family
perheelle = to/for the family, allative case (-lle)

The allative (-lle) ending often expresses:

“to” or “for” someone (beneficiary/recipient)

So:

koko perheelle = for the whole family

Examples:

Tämä pöytä on sopiva koko perheelle.
= This table is suitable for the whole family.
Ostin lahjan lapselle.
= I bought a gift for the child.

Here, yksi (ostoskärry) is “enough for whom?” → for the whole family → koko perheelle.

Why isn’t koko inflected? Why do we say koko perheelle and not something like kokolle perheelle?

Koko is a special word in Finnish: it usually stays in its base form and only the following noun inflects.

So you say:

koko perhe (whole family)
koko perheelle (for the whole family)
koko perheen (the whole family’s)
koko talossa (in the whole house)

The case ending attaches to the main noun (perhe, talo, etc.), not to koko.

Thus koko perheelle is grammatically normal: koko unchanged + perheelle (allative).

Why is there only one question mark if there are two verbs with -ko / -kö?

The sentence is one combined question with two alternative clauses:

Tarvitsetko toisen ostoskärryn,
vai riittääkö yksi koko perheelle?

In English:
Do you need another shopping cart, or is one enough for the whole family?

Both parts are linked by vai and form a single either–or type question, so Finnish uses just one question mark at the end of the whole sentence, even though each clause has its own verb with -ko / -kö.

Could I add sinä and say Tarvitsetko sinä toisen ostoskärryn? Would that sound strange?

You can add sinä:

Tarvitsetko sinä toisen ostoskärryn, vai riittääkö yksi koko perheelle?

This is grammatically correct. The nuance:

Without sinä, it’s a neutral question.
With sinä, it often adds emphasis or contrast, like:
- “Do you need another cart (as opposed to someone else)?”
  or
- “Is it you who needs another cart?”

In a typical shop context, people usually omit sinä and just say Tarvitsetko toisen ostoskärryn..., unless they want that extra emphasis.

Is this sentence polite or informal? How would it change in a very polite form?

Using 2nd person singular (tarvitsetko) is neutral/informal and very typical in everyday interaction, for example between a shop assistant and a customer.

A more formal/polite version would use the teitittely (polite te form):

Tarvitsetteko toisen ostoskärryn, vai riittääkö yksi koko perheelle?

Here:

tarvitsetteko = polite “do you (sir/ma’am) need”

In modern Finland, the neutral sinä / tarvitsetko is already polite enough in most everyday situations, but you may still hear te / tarvitsetteko in more formal or very customer-service‑oriented contexts.