15. The system of claim 12 , wherein, for each respective set of colloquial-speaker vectors, replacing each colloquial-speaker vector of the respective set of colloquial-speaker vectors with the respective, optimally-matched reference-speaker vector from among the reference set of reference-speaker vectors comprises: individually matching all of the colloquial-speaker vectors of each respective set with their respective, optimally-matched reference-speaker vectors, one respective set at a time.
12. A system comprising: one or more processors; memory; and machine-readable instructions stored in the memory, that upon execution by the one or more processors cause the system to carry out operations including: extracting speech features from a plurality of recorded reference speech utterances of a reference speaker to generate a reference set of reference-speaker vectors, for each respective plurality of recorded colloquial speech utterances of a respective colloquial speaker of multiple colloquial speakers, extracting speech features from the recorded colloquial speech utterances of the respective colloquial speaker to generate a respective set of colloquial-speaker vectors, for each respective set of colloquial-speaker vectors, replacing each colloquial-speaker vector of the respective set of colloquial-speaker vectors with a respective, optimally-matched reference-speaker vector from among the reference set of reference-speaker vectors, wherein the respective, optimally-matched reference-speaker vector is identified by matching under a transform that compensates for differences in speech between the reference speaker and the respective colloquial speaker, aggregating the replaced colloquial-speaker vectors of all the respective sets of colloquial-speaker vectors into an aggregate set of conditioned speaker vectors, providing the aggregate set of conditioned speaker vectors to a text-to-speech (TTS) system, and training the TTS system using the provided aggregate set of conditioned speaker vectors.