Overview

SSML (Speech Synthesis Markup Language) lets you control how text is read out loud. It allows you to fine-tune the pronunciation, tone, emphasis, and more to create natural and engaging voice prompts. Below are the most useful SSML commands you can use with SIP Caller to customize your Text-to-Speech experience.

Key SSML Commands

<speak>

• Purpose: The root element for all SSML, ensuring your prompt is processed as SSML.
• Example:

  <speak>Hello! How can I help you today?</speak>

<break>

• Purpose: Adds a pause in speech. Use this to create a natural conversational flow.
• Attributes:
  • time: Duration of the pause (e.g., "500ms" for milliseconds or "1s" for seconds).
• Example:

  <speak>Hello! <break time="500ms"/> How can I assist you?</speak>

<emphasis>

• Purpose: Changes the emphasis on specific words to add expression.
• Attributes:
  • level: Can be "strong," "moderate," or "reduced."
• Example:

  <speak>This is <emphasis level="strong">very important</emphasis> information.</speak>

<prosody>

• Purpose: Controls the pitch, rate, and volume of the spoken text.
• Attributes:
  • rate: Speed of the speech (e.g., "fast," "slow," or percentages).
  • pitch: Pitch of the voice (e.g., "high," "low," or "+10%").
  • volume: Volume level (e.g., "loud," "soft").
• Example:

  <speak><prosody rate="slow" pitch="low">Please listen carefully.</prosody></speak>

<say-as>

• Purpose: Specifies the type of content to help with pronunciation (e.g., dates, times, addresses).
• Attributes:
  • interpret-as: Can be set to "date", "time", "characters", "expletive", etc.
• Example:

  <speak>The date is <say-as interpret-as="date">2024-11-08</say-as>.</speak>

<sub>

• Purpose: Reads an abbreviation or acronym as its full word form.
• Attributes:
  • alias: The full text to be read.
• Example:

  <speak>SIP Caller uses <sub alias="Session Initiation Protocol">SIP</sub> to connect to the PBX.</speak>

<p> and <s>

• Purpose: Defines paragraphs (<p>) and sentences (<s>) to structure longer prompts for better pacing.
• Example:

  <speak><p>Welcome to SIP Caller.</p><p>How can we assist you today?</p></speak>

Quick Tips

• Test Variations: Play around with combinations of <break>, <emphasis>, and <prosody> to find the most natural-sounding prompts.
• Keep it Clear: Overuse of SSML can make prompts sound robotic. Focus on clarity and flow.
• Accessibility: Use <say-as> for dates, times, and special pronunciations to ensure accuracy.

By using SSML effectively in SIP Caller, you can deliver clear, professional, and engaging voice prompts that enhance customer interactions. For further customization, feel free to explore the full SSML specification for Google or SSML specification for Azure and try out different configurations with SIP Caller's Text-to-Speech feature.