Quoting its overview page, Amazon Polly is a cloud service offered by Amazon that lets you to “turn 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 by leveraging machine-learning techniques. These voices also support a Newscaster speaking style that is tailored to news narration use cases.
Finally, Amazon Polly can be leveraged to create unique custom voices.
While Amazon Polly is a paid service, a free tier is available for the first year of usage.