Learn Hardcore Turkish: Şarkı viral oldu.

şarkı is the subject of the sentence and appears in the nominative case. In Turkish, the subject of an intransitive verb (like olmak, “to become”) remains unmarked, so you don’t add any suffix to show definiteness or plurality here.

Why isn’t şarkı in the accusative case (e.g., şarkıyı)?

Because olmak is intransitive—it doesn’t take a direct object. Only transitive verbs require the accusative suffix (-ı, -i, -u, -ü) on their objects. Here, “go viral” describes what the song does (a change of state), so şarkı stays in nominative.

What part of speech is viral, and why is it used exactly like that?

viral is an adjective borrowed from English. It behaves like any Turkish adjective: it’s indeclinable (no case or plural suffix) and goes immediately before the verb when used in a predicate. You’ll often see modern tech or internet terms imported directly.

How does the verb olmak work in viral oldu?

Here olmak means “to become.” The structure is:

Adjective (viral) + ol- (to become) + tense/person suffix.
ol stem + -du past tense = oldu (“became”). So viral oldu literally means “became viral.”

What tense and aspect is conveyed by ?