engine

Specifies the engine (standard, neural or long-form) for Amazon Polly to use when processing input text for speech synthesis. For information on Amazon Polly voices and which voices are available for each engine, see Available Voices.

NTTS-only voices

When using NTTS-only voices such as Kevin (en-US), this parameter is required and must be set to neural. If the engine is not specified, or is set to standard, this will result in an error.

long-form-only voices

When using long-form-only voices such as Danielle (en-US), this parameter is required and must be set to long-form. If the engine is not specified, or is set to standard or neural, this will result in an error.

Type: String

Valid Values: standard | neural | long-form

Required: Yes

Standard voices

For standard voices, this is not required; the engine parameter defaults to standard. If the engine is not specified, or is set to standard and an NTTS-only voice is selected, this will result in an error.