Rosetta Stone is proprietary computer-assisted language learning (CALL) software published by Rosetta Stone Inc. The software uses images, text, sound, and video to teach words and grammar by spaced repetition, without translation. Rosetta Stone calls their approach Dynamic Immersion (a term which they have trademarked). The software's title and logo allude to the Rosetta Stone, an ancient stone slab on which the Decree of Memphis is inscribed in three languages. The three translations gave Jean-Franois Champollion the insight he needed to decipher Egyptian hieroglyphs.