A character communicates by quoting other media.
Unicorn: Butterfly, even one [unicorn]? Tell me that you saw only one.
Butterfly: One? "One alone, to be my own..." "Up goes downwind, up go down!" "Go and catch a falling star..."
Unicorn: Serves me right for even asking you; all butterflies know is songs and poetry and anything else they hear. I guess you mean well. Fly away butterfly.
Butterfly: "Oh, I must take the A train." "Oh, I am a cook and a captain bold and the mate of the Nancy brig." "Has anybody here seen Kelly?"Despite the name, the trope applies equally to characters who use references from other cultural sources, like quoting a book series, using snippets of songs or reciting poetry. This is when a character communicates almost solely by using someone else's words: it can be speeches, books, songs, movies, TV, radio or other mass media. The reasons for this vary: they may have grown up obsessed with the source material or media, have language or memory problems that makes it impossible for them to speak normally, or their education is almost exclusively the quoted source material to the point they are unable to conceive of language or original thought outside of it. In milder cases, they may only use speech patterns, vocabulary and other affectations, but at full tilt they will only and exclusively communicate through quoting others, perhaps even becoming Lost in Character. This can be especially problematic if the source material is limited in scope. Imagine someone in a scifi setting trying to describe the week's Technobabble issues using only lines from Shakespeare. In the case of characters who are unable rather than unwilling to speak using their own words, this trope can eventually be overcome somewhat like learning a new language, with the character making an effort to address their problem. Those who simply choose to speak this may also drop it, though it's unlikely as it tends to be a defining character trait for many. If the character speaks only through a very narrow range of pop-culture references, they tend to get dated very, very fast (and become annoying or anachronistic, though YMMV). Radio Mouth is a Sister Trope / Sub-Trope where someone speaks only through quotes or remixes of messages from TV, film or radio. This is a subtrope of Reference Overdosed.
-- The Last Unicorn [[hottip:*: In order, the songs and poems are: One alone by Sigmund Romberg, unknown, Go and catch a falling star, by John Donne, Take the A Train by Duke Ellington, The Yarn of the 'Nancy Bell by Sir William Schwenck Gilbert and Has Anybody Here Seen Kelly? by Florrie Forde.]]