Bu ayakkabılar çok dar, bu yüzden yürümek zor oluyor.

In Turkish, bu can mean both this and these. It does not change for singular vs. plural.

• bu ayakkabı = this shoe
• bu ayakkabılar = these shoes

The noun shows whether it is singular or plural, not bu.

The plural ending in Turkish is -lar / -ler. You add it once to the noun:

• ayakkabı = shoe
• ayakkabılar = shoes

You choose -lar or -ler by vowel harmony. Since the last vowel in ayakkabı is ı, the correct plural is -lar:

• ayakkabı + lar = ayakkabılar

In Turkish, the verb to be is often omitted in the present tense, especially in simple statements.

So:

• Bu ayakkabılar çok dar literally looks like These shoes very narrow
• but it means These shoes are very tight/narrow

This is completely normal Turkish. English needs are, but Turkish often does not.

Dar literally means narrow or tight.

With shoes or clothes, dar usually means they are too tight for comfort:

• Bu gömlek dar. = This shirt is tight.
• Bu ayakkabılar dar. = These shoes are tight.

So even if the basic meaning is narrow, in this sentence the natural English sense is tight.

Çok means very here, so it comes before the adjective it modifies:

• çok dar = very tight

That is the normal order in Turkish:

• çok güzel = very beautiful
• çok zor = very difficult
• çok dar = very tight

Bu yüzden means because of this, for this reason, or more naturally so / therefore.

It connects the first idea to the result:

• Bu ayakkabılar çok dar, bu yüzden yürümek zor oluyor.
• These shoes are very tight, so walking becomes difficult / is difficult.

It is a very common way to express cause and result.

Yürümek is the dictionary form, the infinitive, meaning to walk or walking.

In this sentence, yürümek functions like a noun phrase: walking.

• Yürümek zor. = Walking is difficult.
• Koşmak eğlenceli. = Running is fun.

So here, Turkish uses the infinitive to talk about the action itself.

Because yürümek is not the direct object here. It is the thing being described as difficult.

• Yürümek zor. = Walking is difficult.

If you used yürümeyi, that would usually mean walking as a direct object of another verb:

• Yürümeyi seviyorum. = I like walking.
• Yürümeyi bıraktı. = He/she stopped walking.

So in your sentence, plain yürümek is the correct form.

Zor oluyor literally means it becomes difficult or it is proving difficult.

• zor = difficult
• oluyor = is becoming / is happening / ends up being

So the sentence suggests a practical, real-life result:

• the shoes are tight,
• and as a result, walking ends up being difficult.

If you said:

• Yürümek zor.

that would mean simply Walking is difficult.

If you say:

• Yürümek zor oluyor.

it sounds a little more like Walking becomes difficult or Walking is difficult in practice / under these circumstances.

The form oluyor is from olmak (to become / to be / to happen) with the progressive ending -yor.

In Turkish, -yor is often used not only for actions happening right now, but also for situations that are currently the case or tend to happen in the present situation.

So zor oluyor can mean:

• it is becoming difficult
• it gets difficult
• it is difficult (in practice, under these conditions)

It sounds natural here because the speaker is describing the current effect of the shoes.

Yes, in a way. Turkish often does not need a separate word like it.

In English, you might say:

• Walking is difficult
• or It is difficult to walk

Turkish uses:

• Yürümek zor
• Yürümek zor oluyor

So there is no dummy subject like English it. The action itself, yürümek (walking / to walk), fills that role.

Yes. That is also correct.

The difference is mainly nuance:

• yürümek zor = walking is difficult
• yürümek zor oluyor = walking becomes difficult / ends up being difficult

The version with oluyor feels a bit more situational or result-oriented. The version without it is more direct and general.

The given order is natural:

• Bu ayakkabılar çok dar, bu yüzden yürümek zor oluyor.

Turkish word order is flexible, but this version is clear and neutral:

1. state the problem
2. give the result

Other orders are possible for emphasis, for example:

• Bu ayakkabılar çok dar; yürümek bu yüzden zor oluyor.

This still makes sense, but the original is more standard for learners.

It can be both, depending on context.

Physical:

• dar pantolon = tight/narrow trousers
• dar kapı = narrow door

More general:

• dar zaman = limited time
• dar alan = confined space

In your sentence, because it is about shoes, dar clearly means tight.

Yes, there are several alternatives, though bu yüzden is very common and neutral.

Some options:

• o yüzden = so / that’s why
• bu nedenle = for this reason
• ondan dolayı = because of that

For everyday speech, bu yüzden and o yüzden are especially common.

It sounds natural. A native speaker could definitely say it.

It is clear, grammatical, and idiomatic:

• Bu ayakkabılar çok dar, bu yüzden yürümek zor oluyor.

In casual speech, some speakers might also say:

• Bu ayakkabılar çok dar, o yüzden yürümek zor oluyor.
• Bu ayakkabılar çok dar, yürümek zor oluyor.

But your original sentence is perfectly natural.