---
name: text-to-speech-ssml-elements
title: SSML elements
description: With the IBM Watson® Text to Speech service, you can use most Speech Synthesis Markup Language (SSML) elements and attributes to control the synthesis of your text.
last-updated: 2025-07-23
---

> ## Documentation Index
> The table of contents for this documentation set is at https://cloud.ibm.com/docs/text-to-speech?format=markdown
> The index for all IBM Cloud docs is at: https://cloud.ibm.com/docs/llms.txt
> Use these files to discover more information as needed.

# SSML elements
{: #elements}

With the IBM Watson® Text to Speech service, you can use most Speech Synthesis Markup Language (SSML) elements and attributes to control the synthesis of your text.
{: shortdesc}

## Supported elements and attributes
{: #elements-summary-table}

Table 1 summarizes the service's support for SSML elements and attributes:

-   *Full* means that the service fully supports the element or attribute with its HTTP and WebSocket interfaces.
-   *Partial* means that the service's support for the element or attribute is limited in one of the following ways:
    -   The service supports only some aspects of the element or attribute.
    -   The service supports the element or attribute with only some of its voices.
    -   The service supports the element or attribute with only one of its interfaces, HTTP or WebSocket.
-   *None* means that the service does not support the element or attribute.

The following sections provide descriptions of each element or attribute, including examples, restrictions, and whether the service's support differs from standard SSML. Support for some attributes and values differs slightly from the SSML specification. For more information, see [W3C Speech Synthesis Markup Language (SSML) Version 1.1](http://www.w3.org/TR/speech-synthesis/){: external}.

| Element or attribute | Support | Element or attribute | Support |
|----------------------|:-------:|----------------------|:-------:|
| [`<audio>` element](#audio_element) | None | [`<prosody>` element](#prosody_element) | Partial |
| [`<break>` element](#break_element) | Full | - contour attribute | None |
| [`<desc>` element](#desc_element) | None | - duration attribute | None |
| [`<emphasis>` element](#emphasis_element) | Partial | - [pitch attribute](#prosody-pitch) | Full |
| [`<express-as>` element](#express-as_element) | Partial | - range attribute | None |
| [`<lexicon>` element](#lexicon_element) | None | - [rate attribute](#prosody-rate) | Full |
| [`<mark>` element](#mark_element) | Partial | - volume attribute | None |
| [`<meta>` element](#mm_element) | None | [`<say-as>` element](#say-as_element) | Partial |
| [`<metadata>` element](#mm_element) | None | - [interpret-as attribute](#say-as-interpret-as) | Partial |
| [`<paragraph>` element](#ps_element) | Full | [`<sentence>` element](#ps_element) | Full |
| [`<phoneme>` element](#phoneme_element) | Full | [`<speak>` element](#speak_element) | Full |
| | | [`<sub>` element](#sub_element) | Full |
| | | [`<voice>` element](#voice_element) | None |
{: caption="SSML elements and attributes"}

## The `<audio>` element
{: #audio_element}

This `<audio>` element inserts recorded elements into the service-generated audio. It is not supported.

## The `<break>` element
{: #break_element}

The `<break>` element inserts a pause into the spoken text. It has the following optional attributes:

-   `strength` specifies the length of the pause in terms of varying strength values:
    -   `none` suppresses a break that might otherwise be produced during processing.
    -   `x-weak`, `weak`, `medium`, `strong`, or `x-strong` insert increasingly stronger breaks.
-   `time` specifies the length of the pause in terms of seconds or milliseconds. Valid value formats are `{integer}s` for seconds or `{integer}ms` for milliseconds.

```xml
Break size <break strength="none"/> no pause
Break size <break strength="x-weak"/> x-weak pause
Break size <break strength="weak"/> weak pause
Break size <break strength="medium"/> medium pause
Break size <break strength="strong"/> strong pause
Break size <break strength="x-strong"/> x-strong pause
Break size <break time="1s"/> one-second pause
Break size <break time="1500ms"/> 1500-millisecond pause
```
{: codeblock}

The `<break>` element is beta functionality for Natural voices.
{: beta}

When used with the time attribute and Expressive or Natural voices, the `<break>` element introduces a pause of approximately the specified duration, though the exact timing may vary based on the voice and context.
{: note}

## The `<desc>` element
{: #desc_element}

The `<desc>` element can occur only within an `<audio>` element. Because the `<audio>` element is not supported, neither is the `<desc>` element.

## The `<emphasis>` element
{: #emphasis_element}

The `<emphasis>` element is supported for use only with the expressive neural voices.
{: note}

With the expressive neural voices, you can use the `<emphasis>` element to emphasize or de-emphasize one or more words of the input text. The element supports an optional `level` attribute that accepts one of the following values:

-   `none` - Prevents the service from emphasizing text that might otherwise be emphasized.
-   `moderate` - Provides a noticeable amount of emphasis to the text. This level is the default if you omit the `level` attribute.
-   `strong` - Provides a more significant amount of emphasis to the text than the moderate level provides.
-   `reduced` - De-emphasizes the text by tending to reduce its significance in the audio. This level is the opposite of stressing the text.

The following example applies the `moderate` level to the word `give`:

```xml
I am going to <emphasis level="moderate">give</emphasis> her the book.
```
{: codeblock}

For more information, see [Emphasizing words](https://cloud.ibm.com/docs/text-to-speech?topic=text-to-speech-synthesis-expressive&format=markdown#syntheses-expressive-word-emphasis).

## The `<express-as>` element
{: #express-as_element}

The `<express-as>` element is an SSML extension specific to the Text to Speech service. It is supported for use only with the expressive neural voices.
{: note}

With the expressive neural voices, you can use the `<express-as>` element to apply speaking styles to enhance the service's emphasis of certain characteristics for all or part of the input text. The element supports a required `style` attribute that accepts one of the following speaking styles:

-   `cheerful` - Expresses happiness and good news.
-   `empathetic` - Expresses empathy and compassion.
-   `neutral` - Expresses objectivity and evenness.
-   `uncertain` - Expresses confusion and uncertainty.

The following example applies the `cheerful` style to the entire input text:

```xml
<express-as style="cheerful">Oh, that&apos;s good news! I&apos;m glad that we could help.</express-as>
```
{: codeblock}

For more information, see [Using speaking styles](https://cloud.ibm.com/docs/text-to-speech?topic=text-to-speech-synthesis-expressive&format=markdown#syntheses-expressive-styles).

## The `<lexicon>` element
{: #lexicon_element}

This `<lexicon>` element introduces pronunciation dictionaries for the given SSML document. It is not supported.

You can use the service's customization interface to define a dictionary of custom entries (word/translation pairs) for use during speech synthesis. For more information, see [Understanding customization](https://cloud.ibm.com/docs/text-to-speech?topic=text-to-speech-customIntro&format=markdown).

## The `<mark>` element
{: #mark_element}

The `<mark>` element is supported only by the service's WebSocket interface, not by its HTTP interface, which ignores the element. For more information, see [Specifying an SSML mark](https://cloud.ibm.com/docs/text-to-speech?topic=text-to-speech-timing&format=markdown#timing-mark).
{: note}

The `<mark>` element is not supported for Natural voices.
{: note}

The `<mark>` element is an empty element that places a marker into the text to be synthesized. The client is notified when all of the text that precedes the `<mark>` element has been synthesized. The element accepts a single `name` attribute that specifies a string that uniquely identifies the mark; the name must begin with an alphanumeric character. The name is returned along with the time at which the mark occurs in the synthesized audio.

```xml
Hello <mark name="here"/> world.
```
{: codeblock}

## The `<meta>` and `<metadata>` elements
{: #mm_element}

The `<meta>` and `<metadata>` elements are containers in which you can place information about the document. They are not supported.

## The `<paragraph>` and `<sentence>` elements
{: #ps_element}

The `<paragraph>` (or `<p>`) and `<sentence>` (or `<s>`) elements are optional elements that can be used to give hints about textual structure. If the text that is enclosed in a `<paragraph>` or `<sentence>` element does not end with an end-of-sentence punctuation character (like a period), the service adds a longer than normal pause to the synthesized audio.

The only valid attribute for either element is `xml:lang`, which allows for language switching. The attribute is not supported.

```xml
<paragraph>
  <sentence>Text within a sentence element.</sentence>
  <s>More text in another sentence.</s>
</paragraph>
```
{: codeblock}

## The `<phoneme>` element
{: #phoneme_element}

The `<phoneme>` element provides a phonetic pronunciation for the enclosed text. The phonetic spelling represents the sounds of a word, how the sounds are divided into syllables, and which syllables receive stress. The element has two attributes:

-   `alphabet` is an optional attribute that specifies the phonology to be used. The supported alphabets are
    -   *The standard International Phonetic Alphabet (IPA):* `alphabet="ipa"`.
    -   *The IBM Symbolic Phonetic Representation (SPR):* `alphabet="ibm"`.

    If no alphabet is specified, the service uses IBM SPR by default. For more information, see [Understanding phonetic symbols](https://cloud.ibm.com/docs/text-to-speech?topic=text-to-speech-symbols&format=markdown).
-   `ph` is a required attribute that provides the pronunciation in the indicated alphabet. The following examples show the pronunciation for the word *tomato* in both formats:

    -   IPA format:

        ```xml
        <phoneme alphabet="ipa" ph="təˈmeɪ.ɾoʊ">tomato</phoneme>
        ```
        {: codeblock}

    -   IPA format with Unicode symbols:

        ```xml
        <phoneme alphabet="ipa" ph="t&#x0259;&#x02C8;me&#x026A;.&#x027E;o&#x028A;">tomato</phoneme>
        ```
        {: codeblock}

    -   IBM SPR format:

        ```xml
        <phoneme alphabet="ibm" ph=".0tx.1me.0Fo">tomato</phoneme>
        ```
        {: codeblock}

For more information about using SPR and IPA notations with the `<phoneme>` element, see [Understanding phonetic symbols](https://cloud.ibm.com/docs/text-to-speech?topic=text-to-speech-symbols&format=markdown).

## The `<prosody>` element
{: #prosody_element}

The `<prosody>` element controls the pitch and speaking rate of the text. All attributes are optional, but an error occurs if you do not specify at least one attribute with the element.

The service supports the following two attributes of the SSML specification:

-   [The `pitch` attribute](#prosody-pitch)
-   [The `rate` attribute](#prosody-rate)

The SSML specification also offers four attributes that the service does not support:

-   The `contour` attribute
-   The `range` attribute
-   The `duration` attribute
-   The `volume` attribute

The service also supports query parameters that let you adjust the rate and pitch for all text of a speech synthesis request. For more information about the parameters and their interaction with the `pitch` and `rate` attributes of the `<prosody>` element, see

-   [Modifying the speaking rate](https://cloud.ibm.com/docs/text-to-speech?topic=text-to-speech-synthesis-params&format=markdown#params-rate-percentage)
-   [Modifying the speaking pitch](https://cloud.ibm.com/docs/text-to-speech?topic=text-to-speech-synthesis-params&format=markdown#params-pitch-percentage)

The `<prosody>` element is not supported for Natural voices.
{: note}

### Differences from the SSML version 1.1 specification
{: #prosody-differences}

The Text to Speech service bases its SSML support on [W3C Speech Synthesis Markup Language (SSML) Version 1.1](http://www.w3.org/TR/speech-synthesis/){: external}. However, the SSML specification has evolved since the service was first released. To maintain backward-compatibility for users, the service continues to support some features of the `<prosody>` element that are different from the latest SSML specification.

-   *For the `pitch` attribute,* the service supports the following additional features:
    -   A relative change in percent indicated by a signed or unsigned number and followed by a `%` (percent sign). The default pitch for a voice is equivalent to passing a value of `0%`.
    -   A relative change in semitones indicated by a signed or unsigned number and followed by the string `st`.

-   *For the `rate` attribute,* the service supports the following additional features:
    -   A relative change in percent indicated by a signed or unsigned number and followed by a `%` (percent sign). The default speaking rate for a voice is equivalent to passing a value of `0%`.
    -   A number with no unit designation specifies the number of words per minute. The number is absolute; you cannot specify a relative increase or decrease in words per minute.

-   *For the expressive neural voices,* the `pitch` and `rate` attributes support only percentage values.
    -   For the `pitch` attribute, do not use Hertz, semitones, or keywords.
    -   For the `rate` attribute, do not use words per minute or keywords.

For more information about the features supported by SSML version 1.1, refer to section [3.2.4 prosody Element](https://www.w3.org/TR/speech-synthesis/#S3.2.4){: external} of the SSML specification.

### The `pitch` attribute
{: #prosody-pitch}

The `pitch` attribute modifies the baseline pitch, or tone, for the text within the element. Accepted values are

-   *A number followed by the `Hz` (Hertz) designation:* The baseline pitch is transposed (up or down) to the specified value. For example, `150Hz`.
-   *A relative change in percent:* A number that causes a relative shift from the default baseline. The number is preceded by `+` (an increase) or `-` (a decrease) and followed by a `%` (percent sign). An unsigned number that is followed by a `%` is interpreted as a positive increase. For example, `+10%` or `10%`. The default pitch for a voice is equivalent to passing a value of `0%`.
-   *A relative change in semitones:* A number that causes an absolute shift from the default baseline. The number is preceded by `+` (an increase) or `-` (a decrease) and followed by `st` (semitones). An unsigned number followed by `st` is interpreted as a positive increase. For example, `+5st` or `5st`.
-   *A keyword:* One of the following six keywords, which modify the pitch to the corresponding predefined values:
    -   `default` uses the service's default baseline pitch.
    -   `x-low` shifts the pitch baseline down by 12 semitones.
    -   `low` shifts the pitch baseline down by six semitones.
    -   `medium` produces the same behavior as `default`.
    -   `high` shifts the pitch baseline up by six semitones.
    -   `x-high` shifts the pitch baseline up by 12 semitones.

Expressive neural voices support only percentage values for the `pitch` attribute. They do not support the use of Hertz, semitones, or keywords.
{: note}

The best way to determine what works for your application is to make adjustments based on percentages and experiment with different values. Try incremental changes of five or ten percent before making more significant modifications.

```xml
<prosody pitch="150Hz">Transpose pitch to 150 Hz</prosody>
<prosody pitch="-20Hz">Lower pitch by 20 Hz from baseline</prosody>
<prosody pitch="+20Hz">Increase pitch by 20 Hz from baseline</prosody>
<prosody pitch="-10%">Decrease pitch by 10 percent</prosody>
<prosody pitch="+10%">Increase pitch by 10 percent</prosody>
<prosody pitch="-12st">Lower pitch by 12 semitones from baseline</prosody>
<prosody pitch="+12st">Increase pitch by 12 semitones from baseline</prosody>
<prosody pitch="x-low">Lower pitch by 12 semitones from baseline</prosody>
```
{: codeblock}

### The `rate` attribute
{: #prosody-rate}

The `rate` attribute indicates a change in the speaking rate for the text within the element. Accepted values are

-   *A number with no unit designation:* The rate is changed to the specified number of words per minute. For example, a value of `50` indicates a speaking rate of 50 words per minute. The number is absolute; you cannot specify a relative increase or decrease in words per minute.
-   *A relative change in percent:* A number that causes a relative shift from the default speaking rate. The number is preceded by `+` (an increase) or `-` (a decrease) and followed by a `%` (percent sign). An unsigned number that is followed by a `%` is interpreted as a positive increase. For example, `+10%` or `10%`. The default speaking rate for a voice is equivalent to passing a value of `0%`.
-   *A keyword:* One of the following six keywords, which modify the speaking rate to the corresponding predefined values:
    -   `default` uses the service's default speaking rate.
    -   `x-slow` decreases the rate by 50 percent.
    -   `slow` decreases the rate by 25 percent.
    -   `medium` produces the same behavior as `default`.
    -   `fast` increases the rate by 25 percent.
    -   `x-fast` increases the rate by 50 percent.

Expressive neural voices support only percentage values for the `rate` attribute. They do not support words per minute or keywords.
{: note}

The best way to determine what works for your application is to make adjustments based on percentages and experiment with different values. Try incremental changes of five or ten percent before making more significant modifications.

```xml
<prosody rate="50">Set speaking rate to 50 words per minute</prosody>
<prosody rate="-5%">Decrease speaking rate by 5 percent</prosody>
<prosody rate="+5%">Increase speaking rate by 5 percent</prosody>
<prosody rate="slow">Decrease speaking rate by 25%</prosody>
<prosody rate="fast">Increase speaking rate by 25%</prosody>
```
{: codeblock}

## The `<say-as>` element
{: #say-as_element}

The `<say-as>` element provides information about the type of text that is contained within the element and specifies the level of detail for rendering the text.

-   The element has one required attribute, `interpret-as`, which indicates how the enclosed text is to be interpreted.
-   The element has two optional attributes, `format` and `detail`, which are used only with particular values of the `interpret-as` attribute, as shown in the following examples.

The service supports the `<say-as>` element with the following languages:

-   The service fully supports the `<say-as>` element for US English.
-   For most other languages, the service supports only the `digits` and `letters` attributes of the element.
-   For Japanese, the service supports only the `digits` attribute. The service ignores non-numeric characters that are included in the string of digits.

The service's default pronunciation of alphabetic, numeric, and alphanumeric strings varies by language, with each language having its own rules. You can use the `<say-as>` element to control how strings are pronounced, including whether they are to be spelled out as individual characters with the `letters` and `digits` elements.

For German, you can also control the pace at which the service pronounces the characters. For more information, see [Specifying how strings are spelled out](https://cloud.ibm.com/docs/text-to-speech?topic=text-to-speech-synthesis-params&format=markdown#params-spell-out-mode).

### The `interpret-as` attribute
{: #say-as-interpret-as}

Acceptable values for the `interpret-as` attribute and examples of each value follow. The service supports the following values as arguments to the `interpret-as` attribute:

-   [`cardinal`](#say-as-cardinal)
-   [`date`](#say-as-date)
-   [`digits`](#say-as-digits)
-   [`interjection`](#say-as-interjection)
-   [`letters`](#say-as-letters)
-   [`number`](#say-as-number)
-   [`ordinal`](#say-as-ordinal)
-   [`vxml:boolean`](#vxml-boolean)
-   [`vxml:currency`](#vxml-currency)
-   [`vxml:date`](#vxml-date)
-   [`vxml:time`](#say-as-time)
-   [`vxml:digits`](#vxml-digits)
-   [`vxml:phone`](#vxml-phone)

#### `cardinal`
{: #say-as-cardinal}

The `cardinal` value speaks the cardinal number for the numeral within the element. The following examples say *Super Bowl forty-nine*. The first is superfluous, since it does not change the service's default behavior.

```xml
Super Bowl <say-as interpret-as="cardinal">49</say-as>
Super Bowl <say-as interpret-as="cardinal">XLIX</say-as>
```
{: codeblock}

#### `date`
{: #say-as-date}

The `date` value speaks the date within the element according to the format given in the associated `format` attribute. The `format` attribute is required for the `date` value. If no `format` is present, the service still attempts to pronounce the date. The following examples speak the indicated dates in the specified formats, where `d`, `m`, and `y` represent day, month, and year.

```xml
<say-as interpret-as="date" format="mdy">12/17/2005</say-as>
<say-as interpret-as="date" format="ymd">2005/12/17</say-as>
<say-as interpret-as="date" format="dmy">17/12/2005</say-as>
<say-as interpret-as="date" format="ydm">2005/17/12</say-as>
<say-as interpret-as="date" format="my">12/2005</say-as>
<say-as interpret-as="date" format="md">12/17</say-as>
<say-as interpret-as="date" format="ym">2005/12</say-as>
```
{: codeblock}

#### `digits`
{: #say-as-digits}

The `digits` value speaks the digits in the number within the element. (The value also pronounces individually any alphabetic characters that are included in the enclosed string.) The following example speaks the individual digits *123456*.

```xml
<say-as interpret-as="digits">123456</say-as>
```
{: codeblock}

#### `interjection`
{: #say-as-interjection}

The `interjection` attribute is an SSML extension specific to the Text to Speech service. It is supported for use only with the expressive neural voices.
{: note}

With the expressive neural voices, the service automatically emphasizes the following interjections: `aha`, `hmm`, `huh`, `oh`, `uh`, `uh-huh`, and `um`. You can use the `interjection` value to enable or disable the service's emphasis of the interjections `aha` and `oh`. Include the additional `enabled` attribute with a value of `true` or `false` to enable or disable the interjection.

The following example disables emphasis of both the `aha` and `oh` interjections in the text:

```xml
<say-as interpret-as='interjection' enabled='false'>Oh</say-as>, in addition, the <say-as interpret-as='interjection' enabled='false'>aha</say-as> wasp is endemic to Australia.
```
{: codeblock}

For more information, see [Emphasizing interjections](https://cloud.ibm.com/docs/text-to-speech?topic=text-to-speech-synthesis-expressive&format=markdown#syntheses-expressive-interjections).

#### `letters`
{: #say-as-letters}

The `letters` value spells out the characters in the word within the element. (The value also pronounces individually any numeric characters that are included in the enclosed string.) The following example spells the letters of the word *hello*.

```xml
<say-as interpret-as="letters">Hello</say-as>
```
{: codeblock}

You can also specify the value `group` or `single` with the optional `format` attribute. These attributes help improve legibility of alphanumeric strings like confirmation of numbers and ID. The `single` format adds more silence while spelling-out characters one-by-one. The `group` format adds a longer silence when we switch from digits to letters and vice-versa, and after reading every 3 or 4 same type of characters.

```xml
<say-as interpret-as="letters" format=“single”>112A567B</say-as>
<say-as interpret-as="letters" format=“group”>3174A2W486</say-as>
```
{: codeblock}

#### `number`
{: #say-as-number}

The `number` value offers an alternative to the `cardinal` and `ordinal` values. You can use the optional `format` attribute to indicate how a series of numbers is to be interpreted. The first example omits the `format` attribute to pronounce the number as a cardinal value. The second example explicitly specifies that the number is to be pronounced as a `cardinal` value. The third example specifies that the number is to be pronounced as an `ordinal` value.

```xml
<say-as interpret-as="number">123456</say-as>
<say-as interpret-as="number" format="cardinal">123456</say-as>
<say-as interpret-as="number" format="ordinal">123456</say-as>
```
{: codeblock}

You can also specify the value `telephone` for the `format` attribute. The examples show two different ways of pronouncing a series of numbers as a telephone number. To pronounce the numbers with the punctuation included, specify the value `punctuation` for the optional `detail` attribute.

```xml
<say-as interpret-as="number" format="telephone">555-555-5555</say-as>
<say-as interpret-as="number" format="telephone" detail="punctuation">555-555-5555</say-as>
```
{: codeblock}

#### `ordinal`
{: #say-as-ordinal}

The `ordinal` value speaks the ordinal value for the digit within the element. The following example says *second first*.

```xml
<say-as interpret-as="ordinal">2</say-as>
<say-as interpret-as="ordinal">1</say-as>
```
{: codeblock}

#### `vxml:boolean`
{: #vxml-boolean}

The `vxml:boolean` value speaks *yes* or *no* depending on the `true` or `false` value within the element.

```xml
<say-as interpret-as="vxml:boolean">true</say-as>
<say-as interpret-as="vxml:boolean">false</say-as>
```
{: codeblock}

#### `vxml:currency`
{: #vxml-currency}

The `vxml:currency` value is used to control the synthesis of monetary values. The string must be written in the format `UUUmm.nn`, where `UUU` is the three-character currency indicator that is specified by ISO standard 4217 and `mm.nn` is the quantity. The following example says *forty-five dollars and thirty cents*.

```xml
<say-as interpret-as="vxml:currency">USD45.30</say-as>
```
{: codeblock}

If the specified number includes more than two decimal places, the amount is synthesized as a decimal number followed by the currency indicator. If the three-character currency indicator is not present, the amount is synthesized as a decimal number only and the currency type is not pronounced. The following example says *forty-five point three two nine US dollars*.

```xml
<say-as interpret-as="vxml:currency">USD45.329</say-as>
```
{: codeblock}

#### `vxml:date`
{: #vxml-date}

The `vxml:date` value works like the `date` value, but the format is predefined as `YYYYMMDD`. If a day, month, or year value is not known or if you do not want it to be spoken, replace the value with a `?` (question mark). The second and third examples include question marks.

```xml
<say-as interpret-as="vxml:date">20050720</say-as>
<say-as interpret-as="vxml:date">????0720</say-as>
<say-as interpret-as="vxml:date">200507??</say-as>
```
{: codeblock}

#### `vxml:time`
{: #say-as-time}

The 'vxml:time' value speaks the time within the element according to the format given in the associated format attribute. The format attribute is required for the time value. The format has to be four digits with either no suffix, "a", "p" or "h". The following examples speak the indicated time in the specified formats, where d, m, and y represent day, month, and year.

```xml
<say-as interpret-as="vxml:time">1230</say-as>
<say-as interpret-as="vxml:time">1230a</say-as>
<say-as interpret-as="vxml:time">1230p</say-as>
<say-as interpret-as="vxml:time">0100h</say-as>
```
{: codeblock}

#### `vxml:digits`
{: #vxml-digits}

The `vxml:digits` value provides the same capabilities as the `digits` value.

#### `vxml:phone`
{: #vxml-phone}

The `vxml:phone` value speaks a phone number with both digits and punctuation. It is equivalent to using the `number` value and specifying `telephone` for the `format` attribute and `punctuation` for the `detail` attribute.

```xml
<say-as interpret-as="vxml:phone">555-555-5555</say-as>
```
{: codeblock}

## The `<speak>` element
{: #speak_element}

The service supports SSML fragments, which are SSML elements that do not include the full XML header. The `<speak>` element is optional for SSML that you pass to the service.
{: note}

The `<speak>` element is the root element for SSML documents. Valid attributes are

-   `version` is a required attribute that specifies the SSML specification. The accepted value is `1.0`.
-   `xml:lang` is not required by the service. Omit the attribute when you use this element. Note that you cannot use this attribute to change the language for a speech synthesis request.
-   `xml:base` has no effect.
-   `xmlns` is not required by the service. Omit the attribute when you use this element.

```xml
<speak version="1.1">
  The text to be spoken.
</speak>
```
{: codeblock}

## The `<sub>` element
{: #sub_element}

The `<sub>` element indicates that the text that is specified by the `alias` attribute is to replace the text that is enclosed within the element when speech is synthesized. The `alias` attribute is the only attribute of the element and is required.

```xml
<sub alias="International Business Machines">IBM</sub>
```
{: codeblock}

## The `<voice>` element
{: #voice_element}

This `<voice>` element requests a change in voice. It is not supported.