って details
Examples
I heard that; they say — casually retelling something heard or said
田中さん、来月結婚するって。
tanaka-san, raigetsu kekkon surutte.
I heard Tanaka's getting married next month. casual
明日、テスト中止だって！やった！
ashita, tesuto chuushi datte! yatta!
I heard tomorrow's test got canceled! Yes! casual
電車、事故でまだ遅れてるんだって。
densha, jiko de mada okureteru n datte.
I heard the trains are still delayed because of an accident. casual
Formation
plain clause + ってattaches to plain clause
Notes
for this quotative; formal or expository writing reaches for という／
とのことだ instead (って is everywhere in SNS and manga prose).
Related patterns
Similar
って is the casual spoken contraction of という／とのことだ, freely dropping だ (来[く]るって) and confined to speech outside formal or expository writing; と言う is the neutral default, equally at home in writing, and never drops だ the way って does.
そうだ has a real register ladder of its own (そうだ→そうです, still hearsay), while って has none — there is no polite version of って itself; the moment more formality is needed, って is replaced wholesale by という／とのことだ rather than softened.