Learn Hardcore Turkish: Kapıyı kilitleyip çık; anahtarı kargocuya bırakma. - Lock the door and leave; don’t leave the key with the courier.

It’s a converb that links two verbs with the same subject, roughly meaning “and (then).” It doesn’t carry its own tense or person; it inherits the mood/tense from the following finite verb. Here, the finite verb is çık (imperative), so kilitleyip is understood as “lock (and then) …”.

Why is there a y in kilitleyip?

It’s a buffer consonant inserted to prevent two vowels from crashing together. The stem kilitle- ends in a vowel, and -ip starts with a vowel, so Turkish inserts -y-: kilitle- + -y- + -ip → kilitleyip. The same buffer appears in:

kapı- + -y- + -ı → kapıyı
kargocu- + -y- + -a → kargocuya

Can I say kilitle ve çık or kilitle çık instead of kilitleyip çık?

Yes.

kilitleyip çık is very natural and compact.
kilitle ve çık explicitly uses ve (“and”); it’s fine, slightly more explicit/bookish.
kilitle çık is common in speech (elliptical coordination).
You’ll also hear kilitle de çık, which is a light, colloquial way to chain commands.

Why do we have kapıyı and anahtarı with the accusative ending?

Because both are definite, specific objects. Turkish marks definite direct objects with accusative:

kapı → kapıyı (the door)
anahtar → anahtarı (the key) Leaving off the accusative would imply an indefinite reading, which doesn’t fit here.

What does kargocuya express, and why the -ya ending?

It’s the dative case, marking the recipient/goal: kargocuya = “to the courier / with the courier (as the person you leave it with).” The construction X-ı Y-ya bırakmak means “to leave X with Y (entrust Y with X).” Contrast:

kargocuya (to/with the courier, recipient)
kargocuda (at the courier’s place, locative)

What exactly is kargocu? Any alternatives?

kargocu is a colloquial term for a delivery person employed by a parcel service. Alternatives:

kurye (courier, often bike/motor courier; also common)
kargo görevlisi (parcel-service employee; neutral/formal)

How is the negative imperative bırakma formed? What are polite/plural versions?

Negative imperative is stem + -ma/-me:

Singular informal: bırakma (don’t leave)
Plural/polite: bırakmayın
Very formal: bırakmayınız Positive counterparts: çık (singular), çıkın (plural/polite), çıkınız (very formal).

Are both actions addressed to the same person, and does -ip force the same subject?

Yes. With -ip, the linked verbs share the same subject as the finite verb that follows. If you need different subjects, you must use a separate finite clause (e.g., with a new verb inflected for person/tense).

Could I reverse the order and say çıkıp kilitle?

Grammatically possible, but it means “leave and then lock,” which is illogical in normal contexts. The -ip chain reflects the order you list, so keep the real-world sequence: kilitleyip çık.

Can I omit kapıyı or anahtarı if the context is clear?

Yes. Turkish often drops recoverable objects:

Kilitleyip çık (if it’s obvious you mean the door)
Kargocuya bırakma (if “the key” is understood) If there’s any risk of ambiguity, keep the object.

How flexible is the word order in the second clause?

Turkish word order is flexible for emphasis. All are possible:

Anahtarı kargocuya bırakma (neutral: DO–IO–V)
Kargocuya anahtarı bırakma (emphasizes the recipient)
Anahtarı bırakma kargocuya (colloquial, puts contrastive focus on the final phrase) The verb typically comes last; moving nouns changes focus/emphasis.

Could I rephrase with -meden/-madan to mean “before leaving”?

Yes: Çıkmadan kapıyı kilitle (“Lock the door before going out”). -madan/-meden means “without/before doing X,” depending on context.

How would I make the whole sentence more polite or formal?

Options:

Plural/polite imperative: Kapıyı kilitleyip çıkın; anahtarı kargocuya bırakmayın.
Very formal: … çıkınız; … bırakmayınız.
Softer request: Kapıyı kilitleyip çıkar mısın; anahtarı kargocuya lütfen bırakma.

Does the semicolon have any special role here?

It simply separates two imperative clauses more strongly than a comma. You could use a period instead. A comma is also possible in informal writing; the meaning stays the same.

How do I say “leave without locking”?

Use a converb of negation:

Kapıyı kilitlemeden çık (leave without locking)
Kapıyı kilitlemeyip çık (not locking and then leaving; similar meaning, slightly different nuance)