Editing Speech synthesis (section)

=== Evaluation challenges ===
The consistent evaluation of speech synthesis systems may be difficult because of a lack of universally agreed objective evaluation criteria. Different organizations often use different speech data. The quality of speech synthesis systems also depends on the quality of the production technique (which may involve analogue or digital recording) and on the facilities used to replay the speech. Evaluating speech synthesis systems has therefore often been compromised by differences between production techniques and replay facilities.

Since 2005, however, some researchers have started to evaluate speech synthesis systems using a common speech dataset.<ref>{{cite web|url=http://festvox.org/blizzard |title=Blizzard Challenge |publisher=Festvox.org |access-date=2012-02-22}}</ref>