It preserves standard writing.
Layer 0 is the ordinary spelling. A12 does not ask communities to abandon their orthography or write everyday text differently.
A12 Code
The layered code for the sound layer flat text leaves out.
A12 is the BantuNomics layered orthography code and codec. It starts with the ordinary spelling a model sees, then adds the sound facts that ordinary spelling does not reliably mark: vowel length, tone, downstep, phrase boundary, and voice quality.
Plain definition
A12 keeps the spelling and adds the missing layers.
The Flat Text Problem exists because ordinary text collapses a spoken Bantu form into a one-dimensional string. A12 reverses that compression in a controlled way. It treats native audio as canonical evidence, aligns that evidence to the syllable, and writes the recoverable sound facts as additive layers.
The design principle is simple: do not destroy the original orthography. Preserve the standard spelling as the base layer, then add explicit layers for the acoustic facts a machine needs but the page does not show.
A12 transform
audio + spelling
->
layers + confidence + provenance
What A12 is and is not
A12 is not a new alphabet. It is a codec for hidden evidence.
It makes sound addressable.
Layers above L0 expose vowel length, tone, downstep, boundary, and voice-quality evidence so models can reason over what native speakers hear.
It is built for audit.
A12 outputs should be traceable to audio, syllable alignment, confidence, and provenance. The point is not decoration; the point is verifiable structure.
Pipeline
From waveform to usable linguistic structure.
Audio plus spelling
A consented native recording is paired with the ordinary spelling, for example ulebomba.
Syllable alignment
The word is parsed into syllables so the vowel nuclei, the tone-bearing positions, are addressable.
Acoustic extraction
Length, F0 contour, downstep, boundary slope, and voice-quality evidence are measured from the signal.
Layer assembly
A12 composes the evidence into additive orthographic layers without destroying the original spelling.
Enterprise output
The resulting layer bundle can support ASR, TTS, MT, pedagogy, corpus annotation, and evaluation workflows.
Codec layers
Each layer adds one missing channel.
L0
Orthography
The standard written form. It is useful for native readers, but it does not encode the full sound layer.
Plain spelling
The input string as written
L1
Mora
The codec reveals concealed vowel length where the audio shows a long nucleus that ordinary spelling does not mark.
Vowel length
Duration and intensity envelope
L2
Tone
Tone marks are attached to the vowel nucleus, because the syllable is the tone-bearing unit.
High and low tone marks
Per-syllable F0 median, slope, and register anchor
L3
Downstep
Downstep marks places where a high tone is realized lower than expected because of tonal structure.
Lowered high-tone markers
F0 contour and local register drop
L4
Phrase Boundary
The phrase edge separates statements, questions, and discourse boundaries that flat text does not expose.
L% or H% phrase edge
Declination slope and final-syllable contour
L5
Voice Quality
Voice quality is a higher acoustic layer. It is not a replacement for tone; it is another channel in the signal.
Phonation / voice-quality cue
H1-H2, jitter, and related acoustic features
uLebomba evidence
The collision is visible once the audio is measured.
The same flat spelling can carry different meanings because the decisive evidence lives in the signal. These artifacts show how the A12 view separates the signal, the sense axis, and the pairwise differences that flat text collapses.
Enterprise use
A12 turns hidden sound evidence into a product surface.
For ASR, TTS, translation, pedagogy, corpus annotation, and model evaluation, the value of A12 is that the missing sound layer becomes addressable. A model no longer sees only one token. It sees the ordinary spelling plus the layered evidence needed to separate meaning.