The TED-LIUM corpus (mirrored here)
is English-language TED talks, with transcriptions, sampled at 16kHz.  It
contains about 118 hours of speech.
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The original page requests that you cite the following paper if you make use of this
corpus:
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  A. Rousseau, P. Deléglise, and Y. Estève, <em>"TED-LIUM: an automatic speech recognition dedicated corpus"</em>, 
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in Proceedings of the Eighth International Conference on Language Resources and Evaluation (LREC'12), May 2012.
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