A Twin Trope. The tendency of twins to banter with each other. This includes Finishing Each Other's Sentences and feeding each other lines, among other things. A common trait of Single-Minded Twins and Telepathic Twins. This can also be done by other multiple siblings, or even Those Two Guys. Truth in Television, especially with twins of the same gender, as sharing one room and being in the same grade means they spend much more time together than average siblings. For that matter, some sets of twins develop a language specific to themselves that no one else understands.