The Timed Text Working Group invites implementations of Timed Text Markup Language 1 (TTML1) (Third Edition) Candidate Recommendation. This document specifies Timed Text Markup Language (TTML), Version 1, also known as TTML1, in terms of a vocabulary and semantics thereof. The Timed Text Markup Language is a content type that represents timed text media for the purpose of interchange among authoring systems. Timed text is textual information that is intrinsically or extrinsically associated with timing information. It is intended to be used for the purpose of transcoding or exchanging timed text information among legacy distribution content formats presently in use for subtitling and captioning functions. In addition to being used for interchange among legacy distribution content formats, TTML Content may be used directly as a distribution format, for example, providing a standard content format to reference from a <track> element in an HTML5 document, or a <text> or <textstream> media element in a [SMIL 2.1] document.