# 031 — Speech Banana

**What a hearing loss hears.**

## The real problem

When someone is diagnosed with hearing loss, the audiogram they're shown is a line graph of decibels across frequency. Technicians and audiologists understand it immediately. Patients — and, more importantly, the families and partners *around* patients — do not. The chart is pure diagnostic data. The connection between "you have a 55 dB loss above 4 kHz" and "that's why you can't understand your grandchildren at a noisy restaurant" is invisible in the standard presentation.

Audiologists bridge that gap verbally, or by pointing at a static "speech banana" diagram pasted into a PDF. The banana shows the region of the audiogram where conversational speech lives. It's a powerful concept, but in its static form it does not let anyone *feel* the consequence of their own hearing curve against it. The leap from "the banana looks like this" to "which specific sounds of English I can no longer distinguish" is left to the patient's imagination.

That gap — between diagnostic shape and lived perception — is where the build lives.

## What was built

An interactive audiogram with the speech banana overlaid and 25 English phonemes positioned at their canonical frequency/loudness coordinates. The user can:

- **Drag** any of the six standard audiometric test-point markers (250, 500, 1k, 2k, 4k, 8k Hz) to sculpt a custom hearing threshold curve in real time
- **Click** one of five preset curves: normal, mild high-frequency loss, moderate presbycusis, severe sensorineural, noise-induced 4 kHz notch
- **Watch** which phonemes fall above the threshold (inaudible — they fade to ~15% opacity) and which remain below it (audible)
- **Read** a test sentence rendered through the current curve. Phonemes the user cannot hear at their loss level are replaced with middle-dots (`·`), so the user sees the exact fricative drop-outs as they would perceive them in conversation
- **Switch** between five sentences specifically constructed to stress the high-frequency fricative region (`s`, `sh`, `th`, `f`, `ch`)

The audible/total counter and loss percentage update live.

## Why this form

The speech banana is already spatial — a 2D region on a 2D chart. Making it interactive is a native next step, not a forced metaphor. The audiogram is the right substrate because it is already the language both audiologists and patients share; the build does not invent a new representation, it animates an existing one and adds the live sentence translator as a new connective organ between "chart" and "experience."

The sentence panel is the core move. Seeing "She sells seashells by the sea shore" become "··e ·e·· ·ea··e··· by ··e ·ea ··ore" under a mild high-frequency loss is the moment the abstract becomes concrete. The dots are not silence; they are the sounds a person *hears as present but cannot distinguish* — the precise mechanism behind the lived complaint *"I can hear you, I just can't understand you."*

This is a threshold-crossing instrument (one curve, many points, some above, some below), but the translation from "point visibility" to "word legibility" is a new storytelling device in the Night Lab catalog. Previous threshold-crossing builds (027 cure-line, 026 cue-pressure) showed when an integral or rate crossed a single line. This build shows what happens *to meaning itself* when many points cross a moving line simultaneously. That is the promotion-candidate move.

## What's actually interesting here

- The speech banana is a *teaching* diagram that has been taped into audiology clinics for decades. Giving it a draggable curve takes almost nothing in engineering terms but unlocks a category of "understand your own diagnosis" tools that currently do not exist
- The preset comparison makes the difference between loss *types* legible, not just loss *severity*. A noise-induced 4 kHz notch and a moderate presbycusis both score around the same total audible-phoneme count but disable *different phonemes*, producing different unintelligibility patterns. The instrument shows this as distinct visual textures, not as numbers
- The live sentence renderer is generative: the same core mechanism could show what the same sentence sounds like across the five curves side-by-side, which would be a strong v1.1 move
- The build is mission-aligned with a2n's "power to the individual" thread: it is a diagnostic tool that explains itself to the patient, not a clinician-only artifact

## Iterations

This is v1.0. No refinement pass beyond the initial build.

Minor polish during implementation: pad the audibility threshold by 2 dB so phonemes exactly at the curve line don't flicker during drag, round dragged values to 5 dB increments (matching clinical audiogram convention), use log-linear interpolation for the threshold between test points (matching how audiologists read charts).

## Next move

The strongest v1.1 would be a **side-by-side comparison mode**: show the same sentence rendered through all five presets simultaneously, so the *difference between loss types* (not just severity) lands in one glance. The second-strongest v1.1 would be **custom audiogram input** — let a real user type in their own audiogram numbers from a recent hearing test and see their own sentence render.

A larger v2.0 would add audio playback via Web Audio API — generate tones at each phoneme frequency and loudness, apply the user's curve as a filter, and let the patient *hear* their own hearing. That would cross from visualization into simulation and would genuinely change the clinical use case. It is also out of scope for the static Night Lab publish flow and would need a different surface.

## Art direction note

Default Night Lab direction. Light editorial monochrome, Geist body + system mono for labels and phonemes, generous negative space, thin borders, no color, no gradients. The audiogram form is already editorial — the build doesn't add decoration, it just gets out of the way. The one small deviation is that the audiogram's Y-axis runs 0→110 dB top-to-bottom, which is the audiology convention (quieter = higher on chart) and visually inverts what most charts do. Keeping that convention is correct because this is an audiology artifact first.

## Promotion candidate read

**Maybe — leaning strong.** This is the first Night Lab build that translates one diagnostic space (chart coordinates) into another lived space (word legibility) via a generative mechanism. The core move — "watch the meaning drop out of this sentence" — is legitimately native to the speech-banana concept and creates a revelation that static diagrams can't. It passes the north star "new legibility" test cleanly: the connection between audiogram geometry and lived unintelligibility becomes visible in a way it previously wasn't.

What keeps it at "maybe" instead of "strong": the v1.0 is still silent. Adding audio would push it into "strong" territory because the current build still requires the viewer to trust that the dots-in-sentence mapping is accurate, whereas audio would let them *confirm it in their ears*. Silent, the build is a powerful explainer; with audio, it would be a diagnostic aid.

The audiology/accessibility domain is fresh for Night Lab and worth returning to — there are adjacent instruments (visual accessibility simulators, speech-in-noise tests, tactile language) that could form a small family of perception-translation builds.
