16. A tangible computer program product for evaluating naturalness of speech utterances by using crowd wisdom models, the tangible computer program product comprising: a non-transitory computer readable storage medium having computer readable program embodied therewith, the computer readable program comprising: computer readable program configured to present a plurality of human-testers with some of the obtained speech utterances; computer readable program configured to receive, for each presented speech utterance, a plurality of corresponding human testers generated speech utterances being human repetitions of the presented speech utterance; computer readable program configured to generate, for each presented speech utterance, an utterance-specific scoring model that is based on the corresponding human-tester generated speech utterances, each scoring model being configured to estimate a level of speech naturalness for the presented speech utterances using at least crowd wisdom models; computer readable program configured to update the scoring model for each presented speech utterance, based on respective human-tester generated speech utterances; and computer readable program configured to derive a speech naturalness score for each presented speech utterance by respectively applying the updated utterance-specific scoring model to each presented speech utterance.
16. A tangible computer program product for evaluating naturalness of speech utterances by using crowd wisdom models, the tangible computer program product comprising: a non-transitory computer readable storage medium having computer readable program embodied therewith, the computer readable program comprising: computer readable program configured to present a plurality of human-testers with some of the obtained speech utterances; computer readable program configured to receive, for each presented speech utterance, a plurality of corresponding human testers generated speech utterances being human repetitions of the presented speech utterance; computer readable program configured to generate, for each presented speech utterance, an utterance-specific scoring model that is based on the corresponding human-tester generated speech utterances, each scoring model being configured to estimate a level of speech naturalness for the presented speech utterances using at least crowd wisdom models; computer readable program configured to update the scoring model for each presented speech utterance, based on respective human-tester generated speech utterances; and computer readable program configured to derive a speech naturalness score for each presented speech utterance by respectively applying the updated utterance-specific scoring model to each presented speech utterance. 20. The tangible computer program product according to claim 16 , further comprising computer readable program configured to present the obtained speech utterances and receive the repetitions over a user interface providing specified incentives to the human testers in return to their repetitions of the respective presented speech utterances.