IBM Watson Text to Speech

Amazon Polly is a service that turns text into lifelike speech, allowing you to create applications that talk, and build entirely new categories of speech-enabled products. Polly's Text-to-Speech (TTS) service uses advanced deep learning technologies to synthesize natural sounding human speech. With dozens of lifelike voices across a broad set of languages, you can build speech-enabled applications that work in many different countries. In addition to Standard TTS voices, Amazon Polly offers Neural Text-to-Speech (NTTS) voices that deliver advanced improvements in speech quality through a new machine learning approach. Polly’s Neural TTS technology also supports two speaking styles that allow you to better match the delivery style of the speaker to the application: a Newscaster reading style that is tailored to news narration use cases, and a Conversational speaking style that is ideal for two-way communication like telephony applications.

The most cost-effective, ultra-realistic text-to-speech API. It sounds more natural-sounding audio than AWS Polly, Microsoft Azure, IBM Watson, and Google Wavenet, and it costs 2 to 4 times less. For interactive applications, the API can return audio in 0.5 seconds for up to 45 seconds of audio (500 characters). For long-form applications, it can product up to 10 hours of audio in 15 minutes (500,000 characters).