Blizzard Challenge the largest, most wide-ranging and authoritative international speech synthesis evaluation campaign, which uses common data sets and a large listening test and is open to all. The aim is to establish a unified text-to-speech testing platform, strengthen communication between speech technology institutions and stimulate speech technology research.

The annual Blizzard Challenge, organized by the ISCA Speech Synthesis Special Interest Group (SynSIG), aims at a better understanding and comparison of research techniques in building corpus-based speech synthesizers using the same speech database for all participants. The challenge is to build one or two synthetic voices using the speech database provided, and synthesize a prescribed set of test sentences. The sentences from each synthesizer are then evaluated through extensive listening tests.