Käytän hengittäviä vaelluskenkiä riippumatta siitä, onko maasto kuiva vai mutainen.

In Finnish, the verb ending already shows the subject, so minä is often omitted.

• käytän = I use / I wear
• the ending -n tells you the subject is I

So Käytän... is a completely natural sentence.
You can add minä for emphasis, but it is not necessary.

Here it means both in a way. Finnish käyttää is broader than English use.

With clothing, shoes, glasses, etc., käyttää often means to wear.

So:

• käytän kenkiä = I wear shoes
• käytän puhelinta = I use a phone

In this sentence, because the object is hiking shoes, the natural English meaning is I wear breathable hiking shoes.

They are in the partitive plural.

Base forms:

• hengittävä = breathable
• vaelluskenkä = hiking shoe

Partitive plural forms:

• hengittäviä
• vaelluskenkiä

This happens because käyttää commonly takes a partitive object when talking generally about using or wearing something, especially when the meaning is not about a specific complete set of items.

So:

• Käytän vaelluskenkiä = I wear hiking shoes / I use hiking shoes
• not necessarily one specific pair being presented as a completed, definite whole

This is very common Finnish object behavior.

Because adjectives agree with the nouns they describe.

So if the noun is in the partitive plural, the adjective must also be in the partitive plural.

• hengittävät vaelluskengät = breathable hiking shoes (nominative plural)
• hengittäviä vaelluskenkiä = breathable hiking shoes (partitive plural)

This kind of agreement is a basic rule in Finnish.

The dictionary form is vaelluskenkä.

Breakdown:

• vaellus = hike, trekking
• kenkä = shoe

Together:

• vaelluskenkä = hiking shoe

The form in the sentence, vaelluskenkiä, is the partitive plural.

Useful forms:

• vaelluskenkä = a hiking shoe
• vaelluskengät = hiking shoes
• vaelluskenkiä = hiking shoes (partitive plural)

riippumatta siitä means regardless of that / regardless of whether...

It is a fixed expression.

• riippua = to depend
• riippumatta = without depending / regardless
• siitä = of that / from that / about that, depending on context

In this sentence, riippumatta siitä, onko... means:

• regardless of whether...

So the whole structure is a standard Finnish way to introduce a clause meaning no matter whether X or Y.

Because the expression is normally riippumatta siitä, että/onko/...

It is a set structure where siitä points forward to the following clause.

You can think of it like this:

• riippumatta siitä = regardless of that
• then the clause explains what that refers to

Here:

• riippumatta siitä, onko maasto kuiva vai mutainen
• regardless of whether the terrain is dry or muddy

So siitä is not random; it is part of the normal grammar of this expression.

Because this is an embedded yes/no question, or a whether-clause.

• onko = is / whether it is

Compare:

• Onko maasto kuiva? = Is the terrain dry?
• En tiedä, onko maasto kuiva. = I don’t know whether the terrain is dry.
• Riippumatta siitä, onko maasto kuiva vai mutainen... = Regardless of whether the terrain is dry or muddy...

So onko is used because the clause means whether the terrain is dry.

Because vai is used in alternatives connected to a question or a whether structure.

Here the clause is effectively:

• is the terrain dry or muddy?
• whether the terrain is dry or muddy

That is why Finnish uses vai.

Very roughly:

• tai = or, in ordinary statements
• vai = or, in questions and question-like alternatives

Examples:

• Haluatko teetä vai kahvia? = Do you want tea or coffee?
• Onko se kuiva vai mutainen? = Is it dry or muddy?

So vai is exactly the right choice here.

Because they are predicate adjectives with a singular subject.

• maasto = terrain
• maasto on kuiva = the terrain is dry
• maasto on mutainen = the terrain is muddy

With a singular subject like maasto, the predicate adjective is usually in the nominative singular:

• kuiva
• mutainen

You would not use kuivaa or mutaista here, because those are partitive forms and would not fit this structure.

Maasto means terrain.

It is a neuter-like noun in Finnish in the sense that Finnish has no grammatical gender. Here it is singular nominative because it is the subject of onko.

• maasto = terrain
• onko maasto kuiva = is the terrain dry

It is a very common word in outdoor, hiking, military, and geography contexts.

Formally, it comes from the verb hengittää = to breathe, so yes, the adjective is related to breathing.

But in actual use, hengittävä for clothing or shoes means:

• breathable

So:

• hengittävät kengät = breathable shoes
• hengittävä takki = breathable jacket

It does not mean the shoes are literally breathing like a person; it means they allow air and moisture to pass through.

Yes, Finnish has other ways to express a similar idea, but this structure is very natural and fairly formal-neutral.

For example, Finnish can also express regardless of with other constructions depending on style and context. But:

• riippumatta siitä, onko maasto kuiva vai mutainen
  is a very standard, clear way to say
• regardless of whether the terrain is dry or muddy

So for a learner, this is a very useful pattern to remember as a whole:

• riippumatta siitä, onko X vai Y = regardless of whether X or Y

A few very useful Finnish patterns appear here:

1. Verb without subject pronoun

   • Käytän already means I use / I wear

2. Partitive plural object

   • hengittäviä vaelluskenkiä

3. Adjective agreement

   • hengittäviä matches vaelluskenkiä

4. Fixed expression

   • riippumatta siitä = regardless of

5. Embedded question

   • onko = whether it is

6. Question-style alternative

   • vai instead of tai

If you understand those pieces, you understand a lot of important Finnish grammar packed into one sentence.