Talvella laitan talvikengät jalkaan, koska ulkona on kylmä.

In this sentence, talvella means in winter. Finnish often uses the adessive ending -lla/-llä with seasons, times, and some time expressions.

So:

• talvi = winter
• talvella = in winter / during winter

This is one of those places where Finnish case usage does not match English prepositions exactly. Even though -lla/-llä often means something like on, at, or with, with seasons it is commonly translated as in:

• kesällä = in summer
• talvella = in winter

Laitan already means I put or I put on, because the verb ending shows the subject.

• laittaa = to put / to place / to put on
• laitan = I put

Finnish often leaves out subject pronouns when they are clear from the verb form.

So:

• (minä) laitan = I put / I put on

You can include minä for emphasis, but it is usually unnecessary.

Yes. Laittaa literally means to put, to place, or to set. But in Finnish it is also commonly used in expressions for putting clothes or shoes on.

So:

• laitan talvikengät jalkaan = I put winter shoes onto my feet
• natural English translation: I put on my winter shoes

Finnish often expresses clothing actions more physically than English does.

Talvikengät is the plural form of talvikenkä, which means winter shoe. In practice, it refers to winter shoes/boots.

Breakdown:

• talvi = winter
• kenkä = shoe
• talvikenkä = winter shoe
• talvikengät = winter shoes

The ending -t marks the plural nominative. Since you normally put on two shoes, Finnish uses the plural.

Also notice the stem change:

• kenkä → kengät

This is a normal sound change in Finnish inflection.

Jalkaan comes from jalka, meaning foot or leg, and here it is in the illative case, which often means into or onto.

So:

• jalka = foot
• jalkaan = into the foot / onto the foot

In this expression, laittaa kengät jalkaan literally means to put shoes onto the feet, but in normal English we would simply say to put on shoes.

This is a very common Finnish structure:

• laittaa hattu päähän = put a hat on one’s head
• laittaa hanskat käteen = put gloves on one’s hand(s)
• laittaa kengät jalkaan = put shoes on one’s feet

This is a great question, because it feels strange from an English point of view.

Finnish often uses the singular in body-part expressions where English might expect a plural. So jalkaan is idiomatic here even though shoes go on both feet.

The phrase laittaa kengät jalkaan is just the standard expression for put on shoes.

Finnish is not focusing on counting individual feet here. It is treating the action as a general clothing action.

Finnish often leaves possession unspoken when it is obvious from context.

So laitan talvikengät jalkaan naturally means:

• I put on my winter shoes

Even though my is not stated, it is clearly understood. In everyday language, Finnish does this a lot with clothes, body parts, and personal items.

If you really wanted to emphasize possession, you could say:

• laitan talvikenkäni jalkaan = I put on my winter shoes

But in normal speech, the shorter version is very common.

Here, koska means because.

So:

• koska ulkona on kylmä = because it is cold outside

Yes, koska can also mean when in some contexts, especially in questions:

• Koska tulet? = When are you coming?

So learners have to use context:

• in a statement like this one, koska usually means because
• in a time question, koska means when

Ulkona means outside / outdoors. It comes from ulkona, a location form meaning in the outside area or outdoors.

Compare:

• ulkona = outside, being outside
• ulos = out / to the outside

So:

• ulkona on kylmä = it is cold outside
• menen ulos = I go outside

In this sentence, the meaning is about location, not movement, so ulkona is the right form.

Finnish often does not use a dummy subject like English it in weather and general-condition expressions.

English says:

• it is cold

Finnish says:

• on kylmä = is cold

You can think of it as there is cold weather or simply a subjectless weather expression.

This pattern is very common:

• on kuuma = it is hot
• on pimeää = it is dark
• on myöhä = it is late

So the lack of it is completely normal in Finnish.

Yes, Finnish word order is fairly flexible, though some orders sound more natural in certain contexts.

This sentence starts with Talvella to set the time frame:

• Talvella laitan talvikengät jalkaan = In winter, I put on winter shoes

Other orders are possible, for example:

• Laitan talvella talvikengät jalkaan
• Talvikengät laitan talvella jalkaan (more marked, more emphasis on the shoes)

The given word order is natural because it introduces the time first, then the action.

Literally, talvikengät means winter shoes. But in real English, depending on the type of footwear, winter boots may sound more natural.

So the exact translation depends on context:

• literal: winter shoes
• more natural in many situations: winter boots

Finnish kenkä can cover footwear more broadly than English shoe sometimes does.

Yes. This is part of Finnish consonant gradation and stem change.

The basic word is:

• kenkä = shoe

But in the plural nominative it becomes:

• kengät = shoes

So the stem changes from kenkä- to kengä- / keng- in inflection.

This is very common in Finnish and something learners gradually get used to. You usually need to learn both the basic form and the inflected stem patterns.

Yes, but the meaning and style are a bit different.

• pukea / puen = to dress / to put on clothing
• laittaa kengät jalkaan = to put shoes on

So puen talvikengät can work, but laitan talvikengät jalkaan is a very natural and concrete way to say I put on my winter shoes.

In everyday Finnish, clothing is often expressed with these body-part phrases:

• laittaa takki päälle = put on a coat
• laittaa kengät jalkaan = put on shoes

So the sentence you have is very idiomatic Finnish.