Tacotron: Revolutionizing Text-to-Speech Synthesis with End-to-End Learning
Tacotron is an end-to-end text-to-speech (TTS) synthesis system that converts text directly into speech, eliminating the need for multiple stages and complex components in traditional TTS systems. By training the model entirely from scratch using paired text and audio data, Tacotron has achieved remarkable results in terms of naturalness and speed, outperforming conventional parametric systems.
The Tacotron architecture has been extended and improved in various ways to address challenges and enhance its capabilities. One such extension is the introduction of semi-supervised training, which allows Tacotron to utilize unpaired and potentially noisy text and speech data, improving data efficiency and enabling the generation of intelligible speech with less than half an hour of paired training data. Another development is the integration of multi-task learning for prosodic phrasing, which optimizes the system to predict both Mel spectrum and phrase breaks, resulting in improved voice quality for different languages.
Tacotron has also been adapted for voice conversion tasks, such as Taco-VC, which uses a single speaker Tacotron synthesizer based on Phonetic PosteriorGrams (PPGs) and a single speaker WaveNet vocoder conditioned on mel spectrograms. This approach requires only a few minutes of training data for new speakers and achieves competitive results compared to multi-speaker networks trained on large datasets.
Recent research has focused on enhancing Tacotron's robustness and controllability. Non-Attentive Tacotron replaces the attention mechanism with an explicit duration predictor, significantly improving robustness and enabling both utterance-wide and per-phoneme control of duration at inference time. Another advancement is the development of a latent embedding space of prosody, which allows Tacotron to match the prosody of a reference signal with fine time detail, even when the reference and synthesis speakers are different.
Practical applications of Tacotron include generating natural-sounding speech for virtual assistants, audiobook narration, and accessibility tools for visually impaired users. One company leveraging Tacotron's capabilities is Google, which has integrated the technology into its Google Assistant, providing users with a more natural and expressive voice experience.
In conclusion, Tacotron has revolutionized the field of text-to-speech synthesis by simplifying the process and delivering high-quality, natural-sounding speech. Its various extensions and improvements have addressed challenges and expanded its capabilities, making it a powerful tool for a wide range of applications. As research continues to advance, we can expect even more impressive developments in the future, further enhancing the potential of Tacotron-based systems.

Tacotron
Tacotron Further Reading
1.Semi-Supervised Training for Improving Data Efficiency in End-to-End Speech Synthesis http://arxiv.org/abs/1808.10128v1 Yu-An Chung, Yuxuan Wang, Wei-Ning Hsu, Yu Zhang, RJ Skerry-Ryan2.Taco-VC: A Single Speaker Tacotron based Voice Conversion with Limited Data http://arxiv.org/abs/1904.03522v4 Roee Levy Leshem, Raja Giryes3.Modeling Prosodic Phrasing with Multi-Task Learning in Tacotron-based TTS http://arxiv.org/abs/2008.05284v1 Rui Liu, Berrak Sisman, Feilong Bao, Guanglai Gao, Haizhou Li4.Non-Attentive Tacotron: Robust and Controllable Neural TTS Synthesis Including Unsupervised Duration Modeling http://arxiv.org/abs/2010.04301v4 Jonathan Shen, Ye Jia, Mike Chrzanowski, Yu Zhang, Isaac Elias, Heiga Zen, Yonghui Wu5.Tacotron: Towards End-to-End Speech Synthesis http://arxiv.org/abs/1703.10135v2 Yuxuan Wang, RJ Skerry-Ryan, Daisy Stanton, Yonghui Wu, Ron J. Weiss, Navdeep Jaitly, Zongheng Yang, Ying Xiao, Zhifeng Chen, Samy Bengio, Quoc Le, Yannis Agiomyrgiannakis, Rob Clark, Rif A. Saurous6.Towards End-to-End Prosody Transfer for Expressive Speech Synthesis with Tacotron http://arxiv.org/abs/1803.09047v1 RJ Skerry-Ryan, Eric Battenberg, Ying Xiao, Yuxuan Wang, Daisy Stanton, Joel Shor, Ron J. Weiss, Rob Clark, Rif A. Saurous7.Probing the phonetic and phonological knowledge of tones in Mandarin TTS models http://arxiv.org/abs/1912.10915v1 Jian Zhu8.An Investigation of the Relation Between Grapheme Embeddings and Pronunciation for Tacotron-based Systems http://arxiv.org/abs/2010.10694v2 Antoine Perquin, Erica Cooper, Junichi Yamagishi9.Emotional End-to-End Neural Speech Synthesizer http://arxiv.org/abs/1711.05447v2 Younggun Lee, Azam Rabiee, Soo-Young Lee10.Multi-reference Tacotron by Intercross Training for Style Disentangling,Transfer and Control in Speech Synthesis http://arxiv.org/abs/1904.02373v1 Yanyao Bian, Changbin Chen, Yongguo Kang, Zhenglin PanTacotron Frequently Asked Questions
What is a Tacotron?
Tacotron is an end-to-end text-to-speech (TTS) synthesis system that converts text directly into speech. It eliminates the need for multiple stages and complex components found in traditional TTS systems. By training the model entirely from scratch using paired text and audio data, Tacotron has achieved remarkable results in terms of naturalness and speed, outperforming conventional parametric systems.
What is the difference between WaveNet and Tacotron?
WaveNet is a deep generative model for generating raw audio waveforms, while Tacotron is an end-to-end text-to-speech synthesis system. WaveNet focuses on generating high-quality audio by modeling the conditional probability distribution of audio samples, whereas Tacotron converts text directly into speech by predicting mel spectrograms from input text. In some cases, Tacotron can be combined with WaveNet to create a complete TTS system, where Tacotron generates mel spectrograms and WaveNet converts them into raw audio waveforms.
What is the difference between Tacotron and Tacotron 2?
Tacotron 2 is an improved version of the original Tacotron system. It maintains the end-to-end text-to-speech synthesis approach but introduces several enhancements, such as a modified architecture, better attention mechanism, and the integration of a WaveNet vocoder for generating high-quality audio waveforms. These improvements result in more natural-sounding speech and better performance compared to the original Tacotron.
How does Tacotron work?
Tacotron works by converting input text into a sequence of linguistic features, such as phonemes or graphemes. These features are then processed by a sequence-to-sequence model with an attention mechanism, which predicts mel spectrograms from the input features. Finally, a vocoder, such as Griffin-Lim or WaveNet, converts the mel spectrograms into raw audio waveforms, resulting in synthesized speech.
What are the practical applications of Tacotron?
Practical applications of Tacotron include generating natural-sounding speech for virtual assistants, audiobook narration, and accessibility tools for visually impaired users. Companies like Google have integrated Tacotron into their products, such as Google Assistant, to provide users with a more natural and expressive voice experience.
What are the main challenges and improvements in Tacotron research?
Some of the main challenges and improvements in Tacotron research include semi-supervised training, multi-task learning for prosodic phrasing, voice conversion tasks, robustness, and controllability. Researchers have developed various extensions and improvements to address these challenges, such as Non-Attentive Tacotron and Taco-VC, which enhance the system's capabilities and performance.
How does Tacotron compare to traditional text-to-speech systems?
Tacotron simplifies the text-to-speech synthesis process by eliminating the need for multiple stages and complex components found in traditional TTS systems. It achieves remarkable results in terms of naturalness and speed, outperforming conventional parametric systems. This makes Tacotron a powerful tool for a wide range of applications, including virtual assistants and accessibility tools.
What is the future of Tacotron and text-to-speech synthesis?
The future of Tacotron and text-to-speech synthesis lies in continued research and development to enhance the system's robustness, controllability, and performance. As research advances, we can expect even more impressive developments, such as improved voice quality, better prosody control, and more efficient training methods. These advancements will further enhance the potential of Tacotron-based systems and expand their applications in various domains.
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