Synthesizing speech recognition training data

A method of computing a plurality of speech synthesis parameter sets representative of a diversity of voices, the method comprising:

• procuring a multiplicity of speech audio recordings of natural people representative of the diversity of voices;
• analyzing the recordings to compute recorded speech vectors within an embedding space of voice features;
• computing a region representing a range of recorded speech vectors within the embedding space;
• and
• learning the plurality of speech synthesis parameter sets by gradient descent according to a loss function computed by:
• synthesizing speech segments according to parameter sets in the plurality of parameter sets;
• analyzing the synthesized speech segments to compute synthesized speech vectors in the space;
• and
• computing a loss in proportion to a clustering of the synthesized speech vectors within the space.