What Are Vocal Biomarkers?
Your voice carries hundreds of measurable signals beyond the words you say. Pitch, rhythm, micro-tremors, harmonic patterns, and spectral characteristics all shift with your emotional and cognitive state — often before you're consciously aware of the change.
These signals are called vocal biomarkers — measurable acoustic features that correlate with emotional states such as stress, confidence, and cognitive load. Unlike self-reported surveys, vocal biomarkers are embedded in natural speech and are difficult to consciously control, making them a valuable complement to traditional coaching tools.
REWRITE analyzes 151+ distinct vocal signals per session, drawing from the full acoustic spectrum to surface patterns worth reflecting on — then presents them as five intuitive dimensions in the Emotional Pentagon™.
Research Foundations
Vocal biomarker science has been studied across multiple disciplines — clinical psychology, neuroscience, computational linguistics, and affective computing. The following peer-reviewed work informs our approach:
Voice & Emotional State Detection
doi.org/10.1002/9781118706664
Stress Detection via Voice
doi.org/10.1145/2370216.2370270
Vocal Markers of Depression & Mental Health
doi.org/10.1016/j.specom.2015.03.004
Confidence & Persuasion in Voice
doi.org/10.1177/0261927X18795924
Cognitive Load & Speech Patterns
doi.org/10.1007/978-3-540-73216-7_111
Longitudinal Vocal Change
doi.org/10.1016/j.bandc.2004.05.003
Our Technology Partner: Emotion Logic
REWRITE's vocal analysis engine is built on technology from Emotion Logic, a voice analytics platform that has spent over a decade developing algorithms for detecting emotional states from speech signals.
Emotion Logic's engine processes voice input through proprietary spectral analysis, extracting biomarker patterns from features including:
- Fundamental frequency (F0) variation — correlates with stress and emotional arousal
- Jitter and shimmer — micro-perturbations linked to cognitive load and fatigue
- Harmonic-to-noise ratio (HNR) — vocal clarity associated with confidence
- Speech rate and pause patterns — rhythm changes indicating processing effort
- Formant trajectories — articulatory shifts reflecting emotional engagement
These raw acoustic features are synthesized into the five dimensions of the Emotional Pentagon™ — making complex signal data immediately understandable.
The Emotional Pentagon™
REWRITE distills 151+ voice signals into five key dimensions, visualized as a pentagon shape that evolves over time:
⚡ Stress
Fight-or-flight activation detected through pitch variability and frequency perturbation. Lower scores indicate a calmer vocal state.
🛡️ Confidence
Vocal certainty measured via harmonic stability, pitch consistency, and speech rate control. Higher scores reflect more self-assured speech.
🔥 Engagement
Emotional presence and connection assessed through energy variation and prosodic dynamics. Higher engagement means you're present, not just going through the motions.
🧠 Cognitive Load
Mental processing strain detected via pause frequency, speech rate irregularity, and filled hesitations. Lower scores indicate clearer, less burdened thinking.
🎯 Authenticity
Alignment between what you say and how your voice behaves, assessed through consistency of vocal features across the session. Higher scores suggest greater emotional congruence.
Each session generates a new pentagon. Over time, you see your shape change — stress shrinking, confidence expanding, engagement deepening. That's transformation you can see, not just feel.
How We Process Your Voice
1. Capture
Your voice is recorded during coaching sessions through the REWRITE app. Audio is captured at high fidelity for acoustic analysis.
2. Analyze
Raw audio is processed through Emotion Logic's engine, extracting 151+ acoustic features in real time. Raw audio is discarded after analysis.
3. Synthesize
Extracted features are mapped to the five Emotional Pentagon™ dimensions using validated scoring algorithms.
4. Visualize
Results appear as your personal Emotional Pentagon™ — a shape you can read at a glance, compared against your own history.
Data handling: Raw voice audio is discarded immediately after analysis — only derived metrics (the pentagon scores and trend data) are retained to track your growth over time. You control your data, and you can request deletion at any time.
Data Security & Compliance
Your voice data is processed with the same rigor applied to the research behind it.
Important: REWRITE is a personal-growth and coaching-support tool. It is not therapy, diagnosis, or treatment. If you are in crisis, contact the 988 Suicide & Crisis Lifeline (call or text 988).
What We Don't Claim
Transparency matters. Here's what REWRITE does not do:
- We don't detect lies. Voice analysis surfaces emotional patterns — it does not determine truth or deception.
- We don't diagnose. REWRITE is not a medical or clinical tool. It does not diagnose depression, anxiety, or any condition.
- We don't replace therapy. If you need professional mental health support, please work with a licensed therapist. REWRITE is a complement to coaching and self-reflection, not a substitute for care.
- We don't guarantee outcomes. Vocal biomarkers provide data points for reflection. Personal growth is complex, and no single tool can promise transformation.
We believe honest tools build trust. That's why we show you exactly what we measure, how we measure it, and what it means.