Learn Hardcore Turkish: İlan duvarda asılı duruyor. - The announcement is hanging on the wall.

afiş = a poster you stick/hang on a wall (most specific for a physical poster)
reklam = ad/commercial (marketing, media)
duyuru = announcement/notice (informational) Using ilan for something hanging on a wall is fine, but if you mean a literal poster, afiş is often the most precise.

Why is it duvarda and not duvar or duvara?

Because -DA/-DE is the locative case meaning “at/on/in.”

duvar + da → duvarda = on/at the wall (location)
duvar + a → duvara = to/onto the wall (direction)
duvar + dan → duvardan = from/off the wall (source)

How is the suffix in duvarda chosen?

Two rules:

Vowel harmony: last vowel in duvar is a (a back vowel) → choose -da (not -de).
Consonant voicing: stems ending in a voiceless consonant take -ta/-te. Since duvar ends with voiced r, we use -da, not -ta. Examples: evde (at home), parkta (in the park).

What does asılı duruyor literally mean, and why both words?

asılı = hanging/suspended (stative adjective/participle)
duruyor = is standing/stays (present continuous of durmak) Together, asılı duruyor means “it is (and remains) hanging,” emphasizing an ongoing state. Turkish often uses durmak with an adjective/adverb to stress a continuing condition.

Can I drop duruyor and just say İlan duvarda asılı?

Yes. İlan duvarda asılı is perfectly natural and means the same in most contexts. Asılı duruyor adds a slight nuance of “is hanging (right now/still).”

How do I say the action “(it) was hung” or “(it) is being hung”?

Use forms of asmak (to hang something) or its passive:

“It was hung (onto the wall)”: Duvara asıldı. (passive, past)
“It is being hung (onto the wall)”: Duvara asılıyor. (passive, present continuous)
“Someone hung it (onto the wall)”: Birisi onu duvara astı. (active, past)

What exactly is asılı morphologically? How is it different from asılmış?

asılı is a stative participle/adjective meaning “hanging, suspended,” derived from the intransitive/passive side of asmak/asılmak.
asılmış is the -mış participle: “(having been) hung.” It highlights a completed action/result. Note: asılmış with a person can mean “hanged,” which is not what you want for a poster. For objects, asılı is the neutral, safe choice.

What does duruyor tell me about tense/aspect?

It’s the present continuous of durmak:

stem: dur-
suffix: -yor, harmonized as -uyor because the last vowel is u → duruyor It signals an ongoing state right now.

Can the word order change?

Yes, Turkish word order is flexible for emphasis:

Neutral/topic-first: İlan duvarda asılı duruyor.
Emphasizing location: Duvarda ilan asılı duruyor.
Afterthought (colloquial): İlan asılı duruyor duvarda. (more informal; avoid in careful writing) The focused element typically appears right before the verb phrase.

Is ilan definite (“the poster”) or indefinite (“a poster”) here?

Without an article, Turkish is context-dependent. As a subject, ilan can be read as either. To make it clearly indefinite, add bir: Bir ilan duvarda asılı duruyor. To make it clearly definite, use a demonstrative: Bu ilan duvarda asılı duruyor.

How do I pronounce the dotted İ and the dotless ı in this sentence?

İ/i (dotted): like English “ee” in “see.” İlan ≈ “EE-lahn.”
I/ı (dotless): a short central vowel, like the “a” in “sofa” (unstressed “uh”). asılı ≈ “ah-suh-luh.” Full rough guide: İlan duvarda asılı duruyor ≈ “EE-lahn doo-VAHR-dah ah-suh-LUH doo-roo-YOR.”

Could I instead say “There’s a notice on the wall”?

Yes: Duvarda bir ilan var.

… bir ilan var states existence.
İlan duvarda asılı (duruyor) describes its state/position (that it’s hanging).

When would I say “on top of the wall” rather than “on the wall”?

Use:

duvarda = on the wall (attached to/against its surface)
duvarın üstünde/üzerinde = on top of the wall (sitting on the top edge/surface) Choose based on the physical relationship.

How can I say “the notice on the wall” as a noun phrase?

Use the -ki suffix to form a relative adjective: duvardaki ilan = “the notice on the wall.”
Example: Duvardaki ilan yırtılmış. = “The notice on the wall is torn.”