1. A system comprising: one or more processors; a computer-readable memory; and a module comprising executable instructions stored in the computer-readable memory, the module, when executed by the one or more processors, configured to: generate an audio representation of a text, wherein the audio representation comprises a sequence of speech segments selected from a plurality of speech segments, wherein the selection of the sequence of speech segments is based at least in part on a plurality of conversion rules, and wherein each speech segment of the sequence of speech segments corresponds to a subword unit of the text; transmit, to a plurality of client devices, the text and the audio representation; receive, from a first client device of the plurality of client devices, first feedback data associated with the audio representation; receive, from a second client device of the plurality of client devices, second feedback data associated with the audio representation; and use the first feedback data and the second feedback data to modify, at least in part, the plurality of speech segments or the plurality of conversion rules.