  In recent years, statistical parametric speech synthesis (SPSS) systems have
been widely utilized in many interactive speech-based systems (e.g.~Amazon's
Alexa, Bose's headphones). To select a suitable SPSS system, both speech
quality and performance efficiency (e.g.~decoding time) must be taken into
account. In the paper, we compared four popular Vietnamese SPSS techniques
using: 1) hidden Markov models (HMM), 2) deep neural networks (DNN), 3)
generative adversarial networks (GAN), and 4) end-to-end (E2E) architectures,
which consists of Tacontron~2 and WaveGlow vocoder in terms of speech quality
and performance efficiency. We showed that the E2E systems accomplished the
best quality, but required the power of GPU to achieve real-time performance.
We also showed that the HMM-based system had inferior speech quality, but it
was the most efficient system. Surprisingly, the E2E systems were more
efficient than the DNN and GAN in inference on GPU. Surprisingly, the GAN-based
system did not outperform the DNN in term of quality.

Audio and Speech Processing;Computation and Language;Sound