Learn Hardcore Turkish: Adresimi yazıp posta kodunu eklemeyi unutmadım. - I wrote my address and didn’t forget to add the postal code.

The suffix -ıp/-ip/-up/-üp makes a converb (a verb-like linker) meaning “and (then)” or “having done X, (then) …”. So yazıp means “writing (it) and then…”. It implies sequence and tight connection, more compact than using ve with two finite verbs. Here it links “writing my address” to the main clause “I didn’t forget to add the postal code.”

Why is it adresimi and not just adresim?

Adresim = “my address.” When it’s a definite direct object of a verb (here, of yazmak “to write”), Turkish marks it with the accusative: adresimi. Without the accusative, adresim yazdım would be ungrammatical; with non-possessed nouns the contrast is clearer: adres yazdım (“I wrote an address, some address”) vs adresi yazdım (“I wrote the address [a specific one]”). With a possessed object like adresim, the accusative becomes adresimi.

Why is it posta kodunu with that extra -n-?

Posta kodu is a compound noun (“postal code”), where kodu carries the 3rd-person possessive suffix (kod-u “its code”). When you add a case suffix (like the accusative) to a possessed noun, you insert a buffer -n-: kodu-nu. So: posta kodu (postal code) → accusative → posta kodunu.

Why does eklemeyi use -meyi and not the dictionary form eklemek?

Verbs like unutmak (“to forget”) take a nominalized verb as their object: -mA + accusative, i.e., ekleme-yi (“adding”). So eklemeyi unutmadım = “I didn’t forget (the act of) adding.” Using eklemek (the infinitive) here is not idiomatic; Turkish prefers the -mA nominalization with unutmak.

What exactly is negated here? Did I not forget both actions?

Grammatically, the negation applies to what is the object of unutmadım, which is only posta kodunu eklemeyi. The -ıp clause (adresimi yazıp) is just an additional action stated as having happened. So the sentence most straightforwardly means “I wrote my address, and I didn’t forget to add the postal code.” If you want to say “I didn’t forget to write my address and (to) add the postal code,” put both actions under unutmak: Adresimi yazmayı ve posta kodunu eklemeyi unutmadım.

Can I replace -ıp with ve here?

You could, but you’d need to make both parts parallel in form. For example:

Adresimi yazdım ve posta kodunu eklemeyi unutmadım. That’s fine, but notice you now have two finite verbs (yazdım, unutmadım). Using -ıp is leaner and emphasizes the sequence: write the address, then (not) forget to add the postal code.

Does unutmadım imply that I actually added the postal code?

In everyday usage, yes: X yapmayı unutmadım strongly implies “I remembered to do X,” and by implication, you did it. Strictly speaking, it states non-forgetting rather than completed action, but pragmatically people understand it as “I did remember and (therefore) did it.”

Why is there no subject pronoun like ben?

Turkish marks the subject on the verb. Unutmadım already shows 1st person singular (the -m ending), so ben is optional and usually omitted unless you want emphasis or contrast.

How does vowel harmony affect yazıp and eklemeyi?

The converb suffix -ip obeys 4-way vowel harmony: -ıp/-ip/-up/-üp. Since yaz- has a back unrounded vowel (a), it becomes yazıp (with ı).
The buffer -y- in ekleme-yi appears because the stem ends in a vowel; the accusative vowel (i) follows 2-way harmony and matches a front vowel (so -yi, not -yı).

Could I say Adresimi yazdıktan sonra posta kodunu eklemeyi unutmadım?

Yes. -DIktan sonra explicitly means “after doing X.” Compared to -ıp, it places stronger emphasis on temporal order (“after I wrote my address, I didn’t forget to add the postal code”). -ıp is lighter and often preferred in narrative flow.

Why is it posta kodu and not postanın kodu?

Turkish commonly forms indefinite noun–noun compounds without the genitive on the first noun: posta kodu (“postal code,” literally “post code-its”). Postanın kodu (“the code of the post/mail”) is grammatical but sounds overly literal or specific; it’s not the set phrase for “postal code.”

Could I make both actions clearly objects of “forget” another way?

Yes:

Adresimi yazmayı da posta kodunu eklemeyi de unutmadım. Using …-yı/-yi da …-yı/-yi de puts both nominalized actions in parallel under unutmadım. You can also say: Adresimi yazmayı ve posta kodunu eklemeyi unutmadım.

What’s the full morphological breakdown of the sentence?

Adres-i-m-i = adres (address) + 1sg poss (-im) + accusative (-i) → “my address (as object)”
yaz-ıp = yaz (write) + converb (-ıp) → “writing (and then)”
posta kod-u-nu = kod (code) + 3sg poss (-u) + accusative with buffer (-nı/-nu → -nu) → “the postal code (as object)”
ekle-me-yi = ekle (add) + nominalizer (-me) + accusative with buffer (-yi) → “(the act of) adding”
unut-ma-dı-m = unut (forget) + negation (-ma) + past (-dı) + 1sg (-m) → “I did not forget”

Could I say yazıp da instead of yazıp?

-ıp da adds a slight contrastive or concessive flavor, often used when the second action is unexpected or contrasting (e.g., “having written it, (still) …”). In your sentence, Adresimi yazıp da posta kodunu eklemeyi unutmadım is possible but sounds like you’re emphasizing “even after writing it, I didn’t (of all things) forget the postal code.” The plain -ıp is neutral and most natural here.

Is there a clearer way to say I both wrote the address and added the postal code (not just that I didn’t forget)?

Yes, just state both actions with finite verbs:

Adresimi yazdım ve posta kodunu da ekledim. This unambiguously says you did both. Adding da after posta kodunu highlights “also.”