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# 添加呼吸音
* 和 *
只有标准 TTS 格式支持此标签。
自然声音语音包括正确说出的字词和呼吸音。通过向合成语音添加呼吸音，可以使合成语音听起来更自然。`` 和 `` 标签可提供呼吸。您有以下选项：
+ 手动模式：您可以在文本中设置呼吸音的位置、长度和音量
+ 自动模式：Amazon Polly 自动将呼吸音插入语音输出
+ 混合模式：由您和 Amazon Polly 共同添加呼吸音
**手动模式**
在手动模式下，可将 `` 标签放在要插入呼吸的输入文本中。您可以分别使用 `duration` 和 `volume` 属性自定义呼吸的长度和音量：
+ `duration`：控制呼吸的长度。有效值为: `default`, `x-short`, `short`, `medium`, `long`, `x-long`。默认值为 `medium`。
+ `volume`：控制呼吸音有多大声。有效值为: `default`, `x-soft`, `soft`, `medium`, `loud`, `x-loud`。默认值为 `medium`。
**注意**
每个属性值的确切长度和音量取决于使用的具体 Amazon Polly 语音。
要使用默认值设置呼吸音，请不带属性使用 ``。
例如，要使用属性将呼吸的持续时间和音量设置为中等，可以按如下方式设置属性：
```
Sometimes you want to insert only a single breath.
```
要使用默认值，只需使用标签：
```
Sometimes you need to insert one or more average breaths so that the
text sounds correct.
```
您可以在一个段落内添加个别呼吸音，如下所示：
```
Wow! That was quite fast. I almost beat my personal best time on this track.
```
**自动模式**
在自动模式下，您使用 `` 标签来告知 Amazon Polly 以适当的时间间隔自动产生呼吸音。您可以设置间隔的频率、音量和持续时间。将 `` 标签放在要应用自动呼吸的文本的开头，然后将结束标签放在文本末尾。
**注意**
与手动模式标签 `` 不同，`` 标签必须具有结束标签 (``)。
您可以将以下可选属性与 `` 标签结合使用：
+ `volume`：控制呼吸音有多大声。有效值为: `default`, `x-soft`, `soft`, `medium`, `loud`, `x-loud`。默认值为 `medium`。
+ `frequency`：控制文本中出现呼吸音的频率。有效值为: `default`, `x-low`, `low`, `medium`, `high`, `x-high`。默认值为 `medium`。
+ `duration`：控制呼吸的长度。有效值为: `default`, `x-short`, `short`, `medium`, `long`, `x-long`。默认值为 `medium`。
默认情况下，呼吸音的频率取决于输入文本。但是，呼吸音通常发生在逗号和句点之后。
以下示例显示如何使用 `` 标签。要确定对您的内容使用哪些选项，请将适用的示例复制到 Amazon Polly 控制台并听其中的差异。
+ 不带可选参数使用自动化模式。
```
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. Amazon Polly is a text-to-speech service that uses advanced deep learning
technologies to synthesize speech that sounds like a human voice. With dozens of lifelike
voices across a variety of languages, you can select the ideal voice and build speech-
enabled applications that work in many different countries.
```
+ 将自动化模式与音量控制结合使用。未指定的参数 (`duration` 和 `frequency`) 设置为默认值 (`medium`)。
```
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. Amazon Polly is a text-to-speech service, that uses advanced deep
learning technologies to synthesize speech that sounds like a human voice. With dozens of
lifelike voices across a variety of languages, you can select the ideal voice and build speech-
enabled applications that work in many different countries.
```
+ 将自动化模式与频率控制结合使用。未指定的参数 (`duration` 和 `volume`) 设置为默认值 (`medium`)。
```
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. Amazon Polly is a text-to-speech service, that uses advanced deep
learning technologies to synthesize speech that sounds like a human voice. With dozens of
lifelike voices across a variety of languages, you can select the ideal voice and build speech-
enabled applications that work in many different countries.
```
+ 将自动化模式与多个参数结合使用。对于未指定的 `Duration` 参数，Amazon Polly 将使用默认值 (`medium`)。
```
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. Amazon Polly is a text-to-speech service, that uses
advanced deep learning technologies to synthesize speech that sounds like a human voice. With
dozens of lifelike voices across a variety of languages, you can select the ideal voice and build
speech-enabled applications that work in many different countries.
```