Chapter 1 explores the development of modern semiotics, while referring to decodification semiotics, interpretation semiotics and notably to Saussure, Peirce and Rossi-Landi. It offers a definition of legal semiotics and introduces the work of Kevelson and Tiefenbrun. It presents Welby’s Significs theory and The Meaning Triad, allowing for an analysis of the sense, meaning and significance of legal terminology. In this context, it examines the Vienna Convention on the Law of Treaties (1969) general rules of treaty interpretation under a legal semiotics lens. It thereafter presents semioethics, which explores avenues to modify problematic signs. The chapter explains how significs and semioethics are applied as methodologies to ‘decode’ the content of international treaties to analyze whether they sufficiently protect the girl child, in light of the intersectional discrimination she encounters. It also discusses the challenges of conducting a semiotic analysis in English, one of the authentic languages of the treaties examined.