Minun pitää korjauttaa talvikengät suutarilla ennen pakkasia.

Because this is a Finnish necessity construction.

With pitää meaning must / have to, the person who has the obligation is put in the genitive:

• minun pitää = I have to
• sinun pitää = you have to
• hänen pitää = he/she has to

The verb pitää itself stays in the 3rd person singular form.

So:

• Minun pitää korjauttaa... = I have to have ... repaired

By contrast, minä pidän would be a different use of pitää, such as:

• Minä pidän kirjasta = I like the book
• Minä pidän kiinni = I hold on

Not in the usual possessive sense.

In Minun pitää, minun is not describing the shoes. It is marking the person who is under the obligation. So it means something like as for me, it is necessary.

That means the sentence does not explicitly say my winter shoes. It just says the winter shoes. In context, people may naturally assume they are the speaker’s shoes.

If you wanted to make the ownership explicit, you could say something like:

• Minun pitää korjauttaa talvikenkäni suutarilla... = I need to have my winter shoes repaired at the shoemaker’s

Korjauttaa means to have/get something repaired by someone else.

Compare:

• korjata = to repair, to fix
• korjauttaa = to have something repaired

So:

• Korjaan kengät. = I repair the shoes.
• Korjautan kengät. = I have the shoes repaired.

In your sentence, the speaker is not fixing the shoes personally. They are arranging for someone else to do it.

It is a causative verb built from korjata.

Very roughly:

• korjata = repair
• korjauttaa = cause to be repaired / have repaired

This -uttaa / -yttää type often adds the idea make someone do X or have X done.

A few similar examples:

• leikata = cut

• leikkauttaa = have something cut, for example have one’s hair cut

• rakentaa = build
• rakennuttaa = have something built

So korjauttaa is a very natural verb here.

Because talvikengät is a total object here: the speaker means the whole shoes/pair should be repaired.

• talvikengät = the winter shoes / winter boots, as a complete set
• talvikenkiä = winter shoes in the partitive, which would sound more indefinite, partial, or ongoing

So:

• Minun pitää korjauttaa talvikengät. = I need to have the winter shoes repaired.
• Minun pitää korjauttaa talvikenkiä. = I need to have some winter shoes repaired / I need to be having winter shoes repaired.

Also, talvikengät is naturally plural because shoes usually come as a pair.

It is a compound word:

• talvi = winter
• kengät = shoes

So talvikengät literally means winter shoes. In real usage, English might translate this as winter shoes or winter boots, depending on context.

The basic singular form is talvikenkä.

Suutarilla means at the shoemaker’s / by a shoemaker.

The ending -lla / -llä is the adessive case. One of its common uses is with people who provide services:

• lääkärillä = at the doctor’s
• hammaslääkärillä = at the dentist’s
• kampaajalla = at the hairdresser’s
• suutarilla = at the shoemaker’s

So here suutarilla does not literally just mean physical location. It also carries the idea of having the work done by that professional.

Normally, no.

With service providers in Finnish, -lla / -llä is the idiomatic choice:

• käydä lääkärillä
• käydä kampaajalla
• korjauttaa kengät suutarilla

Suutarissa would sound unnatural here. The inessive -ssa / -ssä usually means in something, and with a person it does not work in this context.

If you want another natural option, you could say:

• suutarin luona = at the shoemaker’s place

But suutarilla is the most natural form in your sentence.

There are two things going on here.

First, ennen as a preposition takes the partitive:

• ennen joulua = before Christmas
• ennen aamua = before morning
• ennen pakkasia = before the frosts / before freezing weather

Second, pakkaset is often used in the plural in Finnish to mean cold weather, frost, freezing conditions. It does not have to mean several separate individual frosts in a strict counting sense. It often refers more generally to the cold season or the period when freezing temperatures arrive.

So:

• ennen pakkasia = before the freezing weather starts / before the frosts come

Yes. You can say:

• Minun täytyy korjauttaa talvikengät suutarilla ennen pakkasia.

That means almost the same thing.

Both pitää and täytyy are common ways to express necessity:

• minun pitää = I have to
• minun täytyy = I have to

A slightly stronger option would be:

• Minun on pakko korjauttaa... = I absolutely have to / I’m forced to have ...

So pitää is natural and common, but täytyy would also be correct.

No, Finnish word order is fairly flexible. The sentence you have is natural and neutral:

• Minun pitää korjauttaa talvikengät suutarilla ennen pakkasia.

But other orders are also possible if you want to emphasize something different, for example:

• Minun pitää ennen pakkasia korjauttaa talvikengät suutarilla.
• Talvikengät minun pitää korjauttaa suutarilla ennen pakkasia.

The basic meaning stays the same, but the focus shifts a little. In the original sentence, the flow is very natural:

1. who has the obligation
2. what needs to be done
3. what needs work
4. who will do it
5. by when