Amazon Polly

 

• A text-to-speech (TTS) service
• Uses advanced deep learning technologies to convert text into natural, lifelike speech
• It supports saving text into MP3, OGG, and PCM file formats.
• Offers Standard and Neural TTS (NTTS)

Common use cases

• Increase customer engagement
• Language learning applications
• Helps visually impaired individuals to consume digital content
• Testing in-game dialogs
• Voice response

Concepts

• Speech Synthesis Markup Language (SSML)
  • Uses XML-based tags to modify different aspects of the text-to-speech output.
  • Can control pitch, speaking style, speech rate, and volume.
• Standard TTS
  • Concatenates short speech snippets together.
  • Limited in terms of producing different speaking styles.
• Neural TTS
  • Produces higher quality speech output than Standard TTS.
  • Neural TTS supports two speaking styles:
    • Conversational
    • Newscaster
• Speech Mark
  • Refers to the metadata that describes the synthesized speech
  • Speech Mark has four types:
    • Sentence
    • Word
    • Viseme
    • SSML

Features

• Amazon Polly accepts plain text, UTF-8, and SSML as inputs.
• Pronounces out abbreviations and acronyms
• Interprets date/time and unit of measurements.
• Homograph disambiguation 
  • For example,  “St.” can be read as ”saint” or “street.” Amazon Polly is capable of identifying their difference depending on a given context.
• Custom lexicon
  • Supports customizing the pronunciation of words uncommon to the selected language.

Pricing

• Standard TTS
  • $4.00 per 1 million characters
• Neural TTS
  • $16.00 per 1 million characters