| name | ssml-conversion |
| description | Convert plain text into W3C SSML (Speech Synthesis Markup Language) with inferred `<break>`, `<emphasis>`, `<prosody>`, and `<say-as>` tags. Non-destructive: writes to edited/ alongside original/. |
SSML Conversion
Convert plain-text scripts into W3C-compliant SSML by wrapping content in <speak> and inferring semantic markup from textual cues. The output is a valid XML file suitable for any SSML-compatible TTS engine.
When to use
- You have a plain-text script and need SSML for a TTS engine that supports SSML natively (Google Cloud, AWS Polly, Azure)
- You want to add pacing (
<break>), emphasis, and prosody hints without manual markup
- You need W3C-standard output for portability across TTS systems
Inputs to gather
- Source text file (path)
- Optional: working directory for output (defaults to source file's parent)
- Optional: prosody preferences (rate, pitch, volume baseline — applied as defaults in
<prosody>)
Procedure
- Read the source text file and validate UTF-8 encoding.
- Scan for cues and infer markup:
- ALL CAPS text → wrap in
<emphasis level="strong">
- Ellipsis
... → insert <break time="500ms"/> before the next word
- Numbers and dates (e.g., "2024-05-03", "123456") → wrap in
<say-as interpret-as="date" or "digits" as appropriate
- Abbreviations (e.g., "Mr.", "USA", "PhD") → expand or wrap in
<sub alias="expanded-form">abbrev</sub>
- Quoted speech (single or double quotes) → optional: wrap in
<emphasis level="moderate"> or note in decisions log
- Create
<workdir>/original/ and copy the source file unchanged.
- Create
<workdir>/edited/ and write the SSML document there.
- Wrap all content in
<speak> root element and validate as well-formed XML.
- Output filename:
<source-stem>.ssml.xml
- Produce a decisions log (markdown) listing all inferred markup decisions.
Output / side effects
<source-stem>.ssml.xml in <workdir>/edited/ — the complete SSML document ready for TTS<source-stem>.decisions.md — explains which cues triggered which tags and why- Original source file preserved in
<workdir>/original/
Safety / constraints
Non-destructive editing (brand rule): Never overwrite the user's source file. Always create original/ and edited/ subdirectories in the working directory. Default <workdir> to the source file's parent directory; allow the user to override.
SSML validation: Use a standard XML validator (e.g., xmllint) to ensure the output is well-formed before returning. Report any validation errors clearly.
Reference: https://www.w3.org/TR/speech-synthesis11/
