Glossary¶

The research pages use terms from three fields that do not usually meet — speech recognition, human-computer interaction, and text-entry evaluation. This is the shortest useful definition of each, in the sense this project uses it.

Where a term has a stronger claim than it appears to, that is said. Several of the disagreements on these pages are really disagreements about a definition.

Recognition¶

ASR — Automatic Speech Recognition. Audio in, text out. Everything else on this page is about what happens either side of that.

WER — word error rate. Substitutions + insertions + deletions, divided by the number of reference words. The field's default metric, and the source of a specific blind spot: it weights every word equally. A wrong their and a wrong rm -rf count the same, which is why the problem space treats cost-weighted error as a separate, unmeasured thing.

Beam search / greedy decoding — whether the decoder keeps several candidate transcriptions alive or commits to the best next token. Beams cost time and buy accuracy; on a CPU that trade is the whole latency story.

Hallucination — a recogniser emitting fluent text for audio that contained no speech. Whisper is known for it on silence, which is why the silence gate exists before the decoder rather than after it.

Initial prompt — text handed to the decoder as context so it biases toward your vocabulary. YazSes uses it for the personal dictionary and for the app name itself.

Hotword / contextual biasing — the same goal at decode time rather than as a prompt. Stronger, and engine-specific; the reason hotwords is still unwired.

Capture¶

VAD — voice activity detection. Deciding which audio contains speech. YazSes's default is an energy gate: mean(|samples|) against a threshold. Cheap, and the thing most often misconfigured — below your voice and everything is discarded, above the room and nothing is.

Endpointing — deciding when you stopped speaking. Distinct from VAD, which decides whether a moment is speech. Endpointing is what makes release feel instant or laggy. (Confusingly, YazSes's EndpointConfig is about this, not about network endpoints.)

Pre-speech padding — a ring buffer of audio kept from before the key was pressed, prepended to the recording. Without it the first phoneme is clipped, because humans start speaking fractionally before they finish pressing.

Barge-in — speaking while the system is talking back, and having it stop.

Speaker¶

Diarization — "who spoke when". Segmenting audio by speaker without necessarily knowing who they are.

Speaker embedding / d-vector — a fixed-length vector representing a voice, so two utterances can be compared for sameness. Biometric: this is why ADR-019 forbids exporting them under any consent regime.

ECAPA-TDNN — the embedding model YazSes uses by default. Accurate on utterances of a second or more, and unreliable below about half a second, which is exactly why the Cocktail Filter false-rejects the user's own voice and stays off.

Enrolment — recording a known speaker once so later audio can be matched to them. Opt-in and consent-gated here, never automatic.

Language¶

Code-switching — changing language within an utterance, not between sessions. The open question is whether this, rather than accent, is the dominant failure for bilingual users.

LID — language identification. Deciding which language is being spoken. Per-utterance LID is standard; per-span LID is what code-switching needs and what makes it hard.

ITN — inverse text normalisation. Turning spoken forms into written ones: "twenty twenty six" → "2026", "john dot doe at gmail" → an address.

Commands and structure¶

Grammar (Tier 1) — the regex classifier that decides whether an utterance is dictation or a command. Anchored at both ends in this codebase, because ordinary words like "undo" and "cancel" are also commands, and a loose match swallows real speech.

GBNF — the grammar format llama.cpp uses to force a model's output into a schema. How a local model can be made to emit valid tool calls rather than plausible-looking ones.

MCP — Model Context Protocol. The standard interface between an agent and the tools it can call. ADR-020 covers which direction of it YazSes should support and why.

AT-SPI — the Linux accessibility bus. How an application can be asked what has focus and whether it accepts text. The basis of the no-text-target guard, and unavailable on Wayland without it, which is why several capabilities are X11-only.

Evaluation¶

Corrected / uncorrected error rate — errors the user fixed versus errors that survived into the final text. Reporting only the second flatters a system that made the user work hard; reporting only the first hides what shipped. Text-entry research reports both.

MSD error rate — minimum string distance between what was presented and what was produced, normalised. With the two above, the standard set from Soukoreff & MacKenzie.

WPM — words per minute, conventionally with a "word" defined as five characters so that languages and scripts compare. The 153-vs-52 figure on these pages uses this.

Held-out — evaluated on data the model was not tuned on. The bar any personal-adaptation claim has to clear, and the reason that work stays unbuilt rather than merely unfinished.

Preregistration — writing down the hypothesis and analysis before collecting data, so a result cannot be reverse-engineered from what the data happened to show.

This project's own vocabulary¶

Wired / unwired — whether a capability in the registry is reachable from a real entry point. An unwired capability may be fully implemented and tested; it simply has no door. Roughly 62 of 144 are unwired, and the count is enforced by a test so the catalogue cannot overstate itself.

Hold-to-talk — recording only while a key is physically held. The alternative, a toggle, is what produces the "was it listening?" class of problem this project's design avoids.

Egress path — any code that can open an outbound connection, classified fetch (data comes in) or send (user content goes out). There are two of the second kind, and ADR-019 keeps it that way with a test.