Learn Hardcore Turkish: Kiracı fatura tutarını kontrol etti ve dekontu ev sahibine gönderdi. - The tenant checked the bill amount and sent the receipt to the landlord.

Because it’s a definite direct object and takes the accusative. The phrase is a compound: fatura tutarı = “bill amount,” where the head noun tutar carries the 3rd person possessive suffix -(s)I → tutarı. When you add the accusative -(I), a buffer -n- is inserted after a 3rd person possessive: tutar-ı-nı → tutarını. So: “(he/she) checked the bill amount.”

What’s going on morphologically in fatura tutarını?

fatura = bill/invoice
tutar = amount/total
3rd person possessive on the head noun: tutar-ı → “the amount (of the bill)”
Accusative (definite object): buffer -n- + -(I): tutar-ı-nı
Overall: “the bill amount” as a definite object.

Could I say faturanın tutarını instead of fatura tutarını?

Yes. Faturanın tutarı is the full genitive-possessive chain (“the amount of the bill”), and fatura tutarı is the shorter compound form. Both are natural; the full form can sound a bit more explicit or formal. With accusative they become faturanın tutarını and fatura tutarını.

Why is it ev sahibine and not something like ev sahibiye?

Ev sahibi is a compound where the head noun sahip carries 3rd person possessive: sahip + i → sahibi (“the owner of the house”). When you add a case suffix to a 3rd person possessed form, you use the buffer -n-. Dative -(y)e becomes -ne here: sahibi + ne → sahibine. Hence: ev sahibine (“to the landlord/owner”).

Why is dekontu in the accusative? Could it be just dekont?

dekontu = “the receipt/payment slip” (definite object; accusative -(I))
dekont gönderdi = “(he/she) sent a receipt/payment slip” (indefinite; no accusative)
Turkish marks definiteness on objects with the accusative, so the suffix signals “the.”

Is the order dekontu ev sahibine gönderdi normal? I learned that indirect objects usually come before direct objects.

Both orders are possible:

More default/information-neutral: ev sahibine dekontu gönderdi (IO → DO → V)
With focus/emphasis on the direct object: dekontu ev sahibine gönderdi
Turkish allows scrambling for focus; the element right before the verb often feels more prominent.

Why is etti spelled with two t’s in kontrol etti?

The verb is the light-verb construction kontrol etmek (“to check”). Past tense on et- is formed with the -di suffix, which devoices to -ti after a voiceless consonant: et- + -ti → etti (the double t is simply the stem-final t plus the suffix-initial t).

Is kontrol etti the only natural way? What about kontrol yaptı?

Use:

kontrol etti (standard)
kontrolünü yaptı (also fine: “did the check”)
Native verb: denetledi (more formal “inspected”) Avoid kontrol yaptı; it sounds odd without the possessive: prefer kontrolünü yaptı.

What’s the difference between dekont, makbuz, fiş, and fatura?

fatura: invoice/bill (tax document listing items/services and amounts)
fiş: till/receipt from a cash register (store receipt)
makbuz: official receipt acknowledging payment (given by the payee)
dekont: payment slip/proof (often issued by a bank/online transfer confirmation)
In rent contexts, dekont is common as proof of bank transfer.

Why use tutar instead of miktar or ücret?

tutar: the monetary total/amount due (invoice total) — perfect here
miktar: amount/quantity (general; not necessarily money)
ücret: price/fee/wage
bedel: cost/consideration (more formal) So fatura tutarı specifically targets the billed total.

Could I link the two actions without ve, like kontrol edip gönderdi?

Yes:

… kontrol edip … gönderdi (“checked and then sent”)
… kontrol ettikten sonra … gönderdi (“after checking, … sent”)
Both are very natural and slightly tighter than using ve.

Do we need an article for Kiracı? How do we know if it’s “a tenant” or “the tenant”?

Turkish has no articles. Subjects like Kiracı can be read as “a tenant” or “the tenant” from context. Here, the objects are clearly definite because they take the accusative (tutarını, dekontu). If you needed to force indefiniteness for the subject, you could say Bir kiracı….

Does ev sahibi mean only “landlord,” or can it also mean “host/owner”?

It’s flexible:

In rental contexts: ev sahibi = landlord/landlady
In general: homeowner/owner of a house
In social contexts: the host (of a gathering at their place)

What’s the nuance difference between -di past and -miş past here?

kontrol etti … gönderdi: simple, witnessed past — plain statement of fact.
kontrol etmiş … göndermiş: inferential/reported past — the speaker learned or infers it (e.g., from evidence).