Learn Hardcore Turkish: Depoya küçük bir koli geldi. - A small box arrived at the warehouse.

It’s the dative case, marking motion toward a place: depo + (y)a → depoya = to the warehouse. The y is a buffer letter inserted because depo ends in a vowel. The vowel of the suffix follows vowel harmony: the last vowel in depo is back (o), so you get -a (not -e).

Could it be depoda instead? What’s the difference between -da and -a/ya?

-da/-de (locative) = in/at: a static location (no movement). Example: Depoda. = It is in the warehouse.
-a/-e (dative; as -ya/-ye after vowels) = to/toward: used with motion verbs. With gelmek (to come), you need dative: Depoya.

Why is the word order Depoya küçük bir koli geldi and not Küçük bir koli depoya geldi?

Both are grammatical. Turkish is flexible and orders information by topic–focus more than strict SVO/SOV.

Depoya küçük bir koli geldi foregrounds the destination (as the topic).
Küçük bir koli depoya geldi feels more neutral or subject-focused. Meaning is the same; only emphasis shifts.

Can I put the destination after the verb, like Küçük bir koli geldi depoya?

In colloquial speech, postverbal placement can be used for strong contrastive focus (…to the warehouse, not somewhere else). In standard writing, keep complements before the verb: prefer Küçük bir koli depoya geldi or Depoya küçük bir koli geldi.

What does bir mean here—a or one?

Here bir functions as the indefinite article, meaning a. If you want to emphasize the number one, you can stress bir in speech or add tane: bir tane küçük koli = one small package (exactly one).

Where does bir go when there’s an adjective—why küçük bir koli, not bir küçük koli?

küçük bir koli = a small package (default, most natural).
bir küçük koli = one small package (the bir is felt more as the numeral, highlighting the count). Use this when the number matters.

Do I need bir at all? Can I say Depoya küçük koli geldi?

Without bir, it sounds odd here. Bare nouns with adjectives can be interpreted as generic/class-level (small boxes as a kind), not as a single indefinite item. For a single, unspecified item, bir is the natural choice: küçük bir koli.

Why doesn’t koli have the accusative suffix? Shouldn’t it be marked?

Because koli is the subject, not an object, and gelmek (to come) is intransitive—there is no direct object. Subjects are unmarked (nominative). The dative marking is on depoya, the destination.

What exactly is geldi morphologically?

Stem: gel- (come)
Past tense: -DI (allomorphs -dı/-di/-du/-dü by vowel harmony; becomes -tı/-ti/-tu/-tü after voiceless consonants)
3rd person singular: zero ending in the past So gel-
- -di → geldi = he/she/it came; something came. Compare: git-
  - -ti → gitti (went).

How would I say something like “It seems a small package arrived” (evidential/Reported past)?

Use the evidential past -miş: Depoya küçük bir koli gelmiş. This often implies you learned it indirectly (heard/just found out/saw evidence).

If multiple packages arrived, how do I handle the verb—geldi or geldiler?

With a plural non-human subject, both are possible, but singular verb is very common:

Depoya küçük koliler geldi. (natural)
Depoya küçük koliler geldiler. (also correct; can emphasize plurality; more typical with human subjects)

Is koli the same as kutu or paket?

koli: shipping box/carton, often larger or used in logistics.
kutu: box (generic; any box).
paket: package/pack/packet (can be small; also used for wrapped items). In this sentence, koli suggests a shipping carton.

How is Depoya spelled—together or with an apostrophe?

Together, as one word: depoya. Apostrophes are only for proper names: Ankara’ya, Amazon’a. Common nouns do not take an apostrophe.

Any sound/spelling changes I should know when adding -a/-e?

After a vowel-final noun, insert y: oda + a → odaya.
After a consonant-final noun, no buffer: okul + a → okula.
Some consonants soften before vowel-initial suffixes (general rule): kitap + a → kitaba. With depo, you already have a vowel, so it’s depoya.

Pronunciation tips for the sentence?

küçük: both ü are front rounded (like German ü); ç = ch in “chew”.
koli: o is a pure short “o”.
depoya: the y is a glide linking o to a.
geldi: e as in “get”, i as in “machine”; stress typically near the end of the intonational phrase.

How would I say related case forms like “in the warehouse” or “from the warehouse”?

To the warehouse: depoya (dative)
In/at the warehouse: depoda (locative)
From the warehouse: depodan (ablative)