  In this paper, we propose a new approach to pathological speech synthesis.
Instead of using healthy speech as a source, we customise an existing
pathological speech sample to a new speaker's voice characteristics. This
approach alleviates the evaluation problem one normally has when converting
typical speech to pathological speech, as in our approach, the voice conversion
(VC) model does not need to be optimised for speech degradation but only for
the speaker change. This change in the optimisation ensures that any
degradation found in naturalness is due to the conversion process and not due
to the model exaggerating characteristics of a speech pathology. To show a
proof of concept of this method, we convert dysarthric speech using the
UASpeech database and an autoencoder-based VC technique. Subjective evaluation
results show reasonable naturalness for high intelligibility dysarthric
speakers, though lower intelligibility seems to introduce a marginal
degradation in naturalness scores for mid and low intelligibility speakers
compared to ground truth. Conversion of speaker characteristics for low and
high intelligibility speakers is successful, but not for mid. Whether the
differences in the results for the different intelligibility levels is due to
the intelligibility levels or due to the speakers needs to be further
investigated.
