Prosody Tester — Free Vocal Expressiveness & Pacing Analyzer

Q: What is prosody in speech?

Prosody refers to the rhythm, stress, and intonation patterns of speech — how pitch rises and falls, how fast you speak, and where you pause. It's distinct from what words you say; it's how you say them, and it strongly affects how engaging and clear a speaker sounds.

Q: How is a monotone voice measured?

This tool measures the standard deviation of your pitch in semitones, the semitone range between the 10th and 90th percentile of detected pitch values, and the share of time spent in flat 2-second stretches. A narrow range and low variation indicate a more monotone delivery.

Q: Is this analysis scientifically precise?

It computes genuine acoustic measurements (pitch tracking via autocorrelation, energy-based pause detection), but background noise, microphone quality, and a short recording all introduce variability. Treat results as a useful indicator, not a lab-grade voice assessment.

Q: Is my recording uploaded anywhere?

No. The entire analysis runs locally in your browser using the Web Audio API. Nothing is transmitted, stored, or shared.

Q: How can I use this to improve public speaking?

Record a short practice segment, check your pitch range and expressiveness score, then try consciously varying your pitch and adding deliberate pauses before key points. Re-record and compare the numbers to track changes over practice sessions.

What is prosody, and why it matters

Prosody is the melody of speech — the rise and fall of pitch, the rhythm, the pauses, the pace. It's separate from word choice: the same sentence can sound confident, bored, or anxious depending purely on how it's delivered. Listeners pick up on prosody almost instantly, often before consciously processing the words themselves, which is why it has an outsized effect on how engaging, credible, or persuasive a speaker sounds.

What this tool measures

Pitch range

The spread between your typical low and high pitch, measured in semitones — a wider range generally reads as more expressive.

Expressiveness

How much your pitch varies moment to moment relative to your average — low variation reads as monotone.

Pauses

Silent gaps of at least 300ms, detected from the energy envelope — their number and placement shape pacing and emphasis.

Speaking pace

Syllables per second, counted from energy peaks in voiced speech — with and without pauses.

Flat stretches

The share of time spent in 2-second windows where your pitch barely moves — where listeners tend to drift.

Phrase endings

Whether each phrase ends rising, level or falling — frequent rises can make statements sound like questions.

Loudness & emphasis

How much your volume varies, and whether stressed syllables get both higher and louder.

Rhythm & voice clarity

Contrast between long and short syllables (nPVI) and an approximate harmonics-to-noise ratio.

How the pitch contour is built

The recording is resampled to 16 kHz and cut into 25 ms frames every 10 ms. Speech and silence are separated with a threshold that adapts to your microphone's noise floor, so a louder or quieter mic doesn't change the pause count. Pitch is tracked with the YIN algorithm, octave errors are corrected against a local median on both sides of each frame, and all pitch measures are expressed in semitones so low and high voices are compared on the same scale.

Why two takes never give exactly the same numbers

Nobody says the same thing twice with identical melody, speed and pauses — natural variation between takes is real. On top of that, a short recording is a small sample. The tool shows a ± margin for pitch measures, a confidence level for the recording, and keeps your recent takes in this browser so you can compare averages instead of single runs. For the most stable comparison, read the standard passage each time.

Who this is useful for

Public speaking practice — check whether a rehearsed talk sounds flat, and track your expressiveness score across practice runs.
Podcasters and voiceover artists — spot monotone stretches in a recording before publishing.
Interview preparation — energetic, varied delivery is consistently rated more favorably than flat delivery in interview studies.
Language learners — many languages have very different intonation patterns; comparing your contour to a native speaker's can highlight what to work on.
Teachers and presenters — a quick pre-class or pre-talk check on pacing and pause placement.

Limitations

Background noise and microphone distance affect pitch detection accuracy and pause detection.
Syllables are counted from energy peaks, not from a transcript — expect small over- or under-counts, especially in noisy rooms.
A short recording is a snapshot, not a stable trait — record 2–3 takes and look at the average.
What counts as "expressive" varies by context and language — a formal news-reading register is naturally less varied than casual conversation, and that's not a flaw.

Frequently asked questions

What is prosody in speech?

The rhythm, stress, and intonation patterns of speech — how pitch rises and falls, how fast you speak, and where you pause. It's how you say something, not what you say.

How is a monotone voice measured?

Via the standard deviation of your pitch in semitones, the semitone range between the 10th and 90th percentile of detected pitch values, and the share of time spent in flat 2-second stretches.

Why do two recordings of the same voice give different results?

Your delivery naturally changes from one take to the next, and short or noisy recordings add measurement noise. Record at least 20 seconds, read the same passage, keep the same mic distance, and compare the average of several takes.

Is this analysis scientifically precise?

It uses real acoustic measurements, but background noise, mic quality, and a short recording introduce variability — treat it as a useful indicator, not a lab-grade assessment.

Is my recording uploaded anywhere?

No. Everything runs locally in your browser via the Web Audio API. Nothing is transmitted, stored, or shared.

How can I use this to improve public speaking?

Record a practice segment, check your range and expressiveness score, then consciously vary your pitch and add deliberate pauses before key points. Re-record and compare.

Do you sound monotone — or engaging?

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