# Amazon Polly voice engines
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Amazon Polly has four voice engines that convert input text into life-like speech. These include: **Generative**, **Long-form**, **Neural**, and **Standard**. To use an Amazon Polly voice, select an engine and a speech synthesis API operation. Then provide input text for the engine to synthesize, and select an audio output format. Given these inputs, Amazon Polly synthesizes the provided text into a high-quality speech audio stream. 

The following sections include details about the voice engines offered by Amazon Polly. 

**Topics**
+ [Generative voices](generative-voices.md)
+ [Long-form voices](long-form-voices.md)
+ [Neural voices](neural-voices.md)
+ [Standard voices](standard-voices.md)
+ [Choosing a voice engine](using-voices.md)