Learn Hardcore Turkish: Kestirme daha kısa, o yüzden onu seçiyoruz. - The shortcut is shorter, so we choose it.

Here kestirme is a noun meaning shortcut (a shorter route). It can also be used adjectivally in other contexts (e.g., kestirme çözüm = quick-and-dirty fix), but in this sentence it’s the subject: the shortcut.

Is saying Kestirme daha kısa redundant? Doesn’t shortcut already imply being shorter?

It’s natural. You’re comparing two specific options and stating that the shortcut is indeed shorter than the alternative you’re considering. Native speakers say this kind of thing in choices all the time.

Why is there no “to be” verb after kestirme? Should it be kısadır?

Turkish commonly omits the copula in the present. Kestirme daha kısa is complete and colloquial. Kestirme daha kısadır is also correct but more formal or emphatic.

How does daha make the comparative? How would I say “shorter than X” or “the shortest”?

Comparative: daha + adjective → daha kısa = shorter.
Name the thing you’re comparing to with ablative -den/-dan: normal yoldan daha kısa = shorter than the normal route.
Superlative: en + adjective → en kısa = the shortest.
Intensifiers: çok daha kısa (much shorter), biraz daha kısa (a bit shorter).

What is the nuance of o yüzden? Could I use bu yüzden, bu nedenle, or bu sebeple instead?

They all mean so/therefore, with small differences:

o yüzden: for that reason; very common in speech.
bu yüzden: for this reason; points more to the immediately mentioned cause.
bu nedenle/sebeple: therefore; a bit more formal. All work here. Since you just stated the reason, bu yüzden is also very natural, but o yüzden is extremely common and fine.

Can I use çünkü here?

Yes, but the structure changes because çünkü means because and introduces the reason:

Therefore-version: Kestirme daha kısa, o/bu yüzden onu seçiyoruz.
Because-version: Onu seçiyoruz çünkü kestirme daha kısa. Don’t combine them (avoid çünkü o yüzden).

Why is it onu, not o? What does the -u ending do?

O is the 3rd‑person pronoun (he/she/it). As a definite direct object, it takes the accusative: o + (n)u → onu. This marks it as specific: it (that shortcut). Common case forms: onun (genitive), ona (dative), onda (locative), ondan (ablative).

Could I drop onu and just say … o yüzden seçiyoruz?

Yes. Turkish often omits understood objects. O yüzden seçiyoruz still means we choose it for that reason. Keeping onu explicitly links to kestirme and is also natural.

Why not repeat the noun as kestirmeyi seçiyoruz instead of using onu?

That’s fine too: kestirme + accusative -(y)i → kestirmeyi seçiyoruz. Speakers often switch to the pronoun onu to avoid repeating the noun once it’s known. Both are natural.

Is the word order fixed? Can I move things around?

Word order is flexible for emphasis:

Neutral/common: … o yüzden onu seçiyoruz.
Emphasizing the reason: … bu yüzden onu seçiyoruz.
Emphasizing the choice: … onu bu yüzden seçiyoruz.
Postverbal object is possible in speech: … seçiyoruz onu, but onu seçiyoruz is more neutral.

Why seçiyoruz (we are choosing)? Could I say seçeriz or seçeceğiz?

seçiyoruz (-iyor): present continuous/immediate decision → so we’re choosing it (now/this time).
seçeriz (aorist): habitual/general tendency → in such cases, we choose it.
seçeceğiz (future): future decision → so we will choose it. Pick the one that matches your meaning.

Is the comma before o yüzden correct? Could I use a period or semicolon?

Yes. Turkish commonly links such clauses with a comma. A period or semicolon is also fine:

Kestirme daha kısa. O yüzden onu seçiyoruz.
Kestirme daha kısa; o yüzden onu seçiyoruz.

How would I say “shorter than the normal road” explicitly?

Use the ablative on the comparator:

Normal yoldan daha kısa.
Diğer yoldan daha kısa.
Ana yoldan daha kısa.

Do I need an article like the or a for kestirme? How do I show definiteness?

Turkish has no articles. Definiteness is mostly shown by context and by accusative on objects.

As subject: kestirme can mean the shortcut (the one in context).
As object: definite kestirmeyi or pronoun onu; indefinite leaves off accusative (e.g., bir kestirme seçiyoruz = we’re choosing a shortcut).

Can I make a single-clause version with because using a nominal clause?

Yes: Kestirme daha kısa olduğu için onu seçiyoruz. Here -DIĞI için forms a because‑clause and sounds a bit more formal.