Storyline 360: SSML Support

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Enrich the way your learners experience text-to-speech audio. As of December 2023, Storyline 360 supports speech synthesis markup language (SSML). Now you can adjust the speaking rate, modify pronunciation, add pauses, and more to boost clarity and interest. Read on for details.


To enable SSML support, you must enclose your text-to-speech narration with a pair of <speak> tags. This tag is supported for neural and standard voices. Once SSML support is enabled, the Insert Text-to-Speech window includes syntax highlighting so you can easily add tags and identify SSML-enhanced text. Check out this screenshot for an example. (Click the image to enlarge it.)

Insert Text-to-Speech window in Storyline 360.

View Supported SSML Tags

SSML tags work for all standard voices. However, neural voices have fewer tag options. For example, neural voices don't support emphasizing words. The table below lists all available SSML tags and their supported voice(s).

Learn more about using SSML and supported SSML tags.



Supported Voice(s)

Add a Pause


Neural and standard voices

Emphasize words


Standard voices

Place a Custom Tag in Your Text

<mark name="tag_name"/>

Neural and standard voices

Add a Pause Between Paragraphs


Neural and standard voices

Use Phonetic Pronunciation


Neural and standard voices

Control Volume, Speaking Rate, and Pitch


Standard voices. However, neural voices can support the volume and speaking rate attributes.

Set a Maximum Duration for Synthesized Speech

<prosody amazon:max-duration>

Standard voices

Add a Pause Between Sentences


Neural and standard voices

Control How Special Types of Words Are Spoken


Except for the characters or spell-out attribute, this tag is supported by both neural and standard voices

Identify SSML-Enhanced Text


Neural and standard voices

Pronounce Acronyms and Abbreviations


Neural and standard voices

Add the Sound of Breathing


Standard voices

Newscaster speaking style

<amazon:domain name="news">

Select neural voices (Matthew (en-US), Joanna (en-US), Lupe (es-US), and Amy (en-GB)

Add Dynamic Range Compression

<amazon:effect name="drc">

Neural and standard voices

Speak Softly

<amazon:effect phonation="soft">

Standard voices

Control Timbre

<amazon:effect vocal-tract-length>

Standard voices


<amazon: effect name="whispered">

Standard voices

Tip: Creating content in various languages? Choose the voice, then use English-language SSML tags—even if your content is in a language other than English.

How to Fix Invalid SSML Tags

When you add SSML tags to your text-to-speech narration, you might see this error message: Storyline 360 can't convert this text to speech. Verify the SSML tags are correct and supported for the selected voice.

Here are a few troubleshooting tips:

  • Make sure your text-to-speech narration has opening and closing speak tags: <speak></speak> and that each SSML tag has the appropriate opening and closing tags where applicable: <emphasis></emphasis>,<p></p>.
  • Ensure the SSML tags are supported for the selected voice.
  • Check that the syntax highlighting only applies to the SSML tags, not the script text.

Test a Sample Narration With SSML Tags

Want to see SSML support in action? Check out this example to hear the difference between narration with and without SSML tags.

Storyline 360 slide example.

Understand Compatibility

SSML support is exclusive to Storyline 360 as of December 2023. When you open, edit, and publish projects with text-to-speech narration and SSML tags in Storyline 3 and earlier versions of Storyline 360, the narration will work as expected. However, you can't create new text-to-speech narration or change the language, voice, script, or SSML tags for existing narration in Storyline 3.

Note that updating existing narration with new SSML tags in earlier versions of Storyline 360 will break SSML support.

Learn more about compatibility.

Share Your Feedback

What excites you most about SSML support? How will you use this feature to help learners? We'd love your feedback!