Speech processing
A Practical Text-to-Speech Evaluation Guide
Compare synthetic speech with listening tests, pronunciation checks, latency, stability, and language-specific slices.
A voice demo may sound impressive on one sentence and fail on names, numbers, or long passages. Evaluate speech generation with the text and listening conditions your product actually uses.
Prepare the script
Create a held-out script covering short replies, long paragraphs, dates, currency, abbreviations, uncommon names, punctuation, and each supported language. Include text that is likely to expose skipped or repeated words. Keep speakers and recording levels consistent during listening tests, and randomize sample order so a familiar brand does not bias ratings.
Rate more than naturalness
Ask fluent listeners to rate intelligibility, pronunciation, prosody, and whether the audio preserves every word. Record disagreement and inspect outliers. A separate transcription pass can reveal omissions, but an automatic recognizer can make its own mistakes; manually verify important cases. For multilingual products, report each language and accent separately rather than averaging them away.
Measure deployment behavior
Record time to first playable audio, total generation time, real-time factor, audio glitches, and failure rate under expected concurrency. Use the same hardware or service tier and text for each candidate. The Transformers TTS guide shows the task and available model workflows, but a model list alone is not a quality ranking.