Since 2007, the TED Conference has been posting on its website all video recordings of its talks, English subtitles and their translations in tens of languages. In order to make this collection of talks more effectively usable by the research community, the original textual contents are redistributed through the WIT3 (Web Inventory of Transcribed and Translated Talks) website, together with MT benchmarks and processing tools.

For a detailed description of this corpus, read:

M. Cettolo, C. Girardi, and M. Federico. 2012. WIT3: Web Inventory of Transcribed and Translated Talks.
In Proc. of EAMT, pp. 261-268, Trento, Italy. pdf.