Text-to-Speech
Text-to-Speech (TTS) describes automatic generation of spoken audio from text, often using neural models. It covers quality, prosody, latency, privacy and integration aspects.
Classification
- ComplexityHigh
- Impact areaTechnical
- Decision typeTechnical
- Organizational maturityIntermediate
Technical context
Principles & goals
Use cases & scenarios
Compromises
- Misuse for deepfake audio and identity fraud
- Violation of personal and copyright rights for voices
- Insufficient privacy measures at cloud providers
- Use SSML consistently to control prosody
- Run A/B tests to choose voices and parameters
- Ensure privacy via anonymization and minimal storage
I/O & resources
- Raw text or structured content (SSML)
- Voice profiles and configuration data
- System requirements for latency, accessibility and privacy
- Streaming audio (OPUS, PCM) or audio files (MP3, WAV)
- Diagnostic logs and metrics
- Metadata about voice, language and synthesis parameters
Description
Text-to-Speech (TTS) refers to automatic generation of spoken audio from text using rule-based or neural synthesis methods. The concept covers quality, prosody, latency, privacy and integration requirements within product and platform architectures. It focuses on architectural choices, operational models and ethical considerations.
✔Benefits
- Improved accessibility for users with impairments
- Automated audio generation reduces production effort
- Scalable delivery of voice interfaces
✖Limitations
- Natural intonation and emotion remain limited
- Voice quality varies widely by model and language
- High compute cost for real-time neural models
Trade-offs
Metrics
- Words-per-second (WPS)
Measures output rate; important for latency assessment.
- MOS (Mean Opinion Score)
Subjective quality rating from user studies.
- Pronunciation error rate
Share of incorrectly generated or unintelligible outputs.
Examples & implementations
Read-aloud feature for news app
Integration of a TTS engine to read articles aloud to users; focus on voice quality and offline caching.
IVR voices for customer support
Cloud TTS provides dynamic prompts in multiple languages, including GDPR-compliant data handling.
Accessible learning platform
Automatic audio versions of learning materials increase accessibility for visually impaired users.
Implementation steps
Requirements analysis (quality, latency, privacy)
Select engine (cloud vs. on-premise) and voice
Integrate, test (MOS, intelligibility) and monitor
⚠️ Technical debt & bottlenecks
Technical debt
- Outdated models without deprecation plan
- Missing infrastructure for efficient scaling
- Incomplete test data for edge cases and dialects
Known bottlenecks
Misuse examples
- Creating deceptively realistic voices without consent
- Uncritical use of low-quality voices in critical systems
- Sharing sensitive text with non-GDPR-compliant services
Typical traps
- Underestimating the importance of text normalization
- Lack of performance tests for real user load
- Ignoring legal risks in voice synthesis
Required skills
Architectural drivers
Constraints
- • Language support limited per model
- • Legal restrictions for voice licenses
- • Costs at high throughput or low latency