Tone
Tone lives in the syllable.
Tone is a pitch element or register added to a syllable to convey grammatical or lexical information. In Bantu languages, it is not decoration, stress, or emphasis. It is meaning. Change the tone on a syllable and you may get a different word, a different statement, or a different sentence.
Tone has to live somewhere.
It does not float over the word. It does not attach to the morpheme. It is not painted onto ordinary orthography. In Bantu languages, tone docks on the syllable nucleus: the vowel. That makes the syllable the Tone-Bearing Unit, or TBU.
(prenasal)(onset)(aspiration)(glide) + nucleus
| Slot | Name | Examples | Carries tone? |
|---|---|---|---|
| N | Prenasal | mb, nd | No |
| C | Onset | k, t, b | No |
| H | Aspiration | ph, th | No |
| G | Glide | w, y | No |
| V | Nucleus / TBU | a, e, i, o, u | Yes |
u-le-bo-mba: four syllables, four docking points.
A model that sees eight letters has not yet found the language. The Bemba word
ulebomba resolves as u-le-bo-mba: four syllables, four vowels,
four places where tone can dock. Tone, vowel length, downstep, and phrase-boundary
signals attach to those syllabic positions.
The dependency chain
No syllables, no tone. No tone, no meaning.
- Meaning in Bantu is often decided by tone.
- Tone attaches to the syllable nucleus, the V.
- The V can only be located after the syllable is located.
- The syllable requires the language's Full Syllable Inventory.
- Without the FSI, a model is guessing at the unit that carries meaning.
The punchline for frontier AI.
No frontier LLM can enumerate the full syllable inventory of any of the 500+ Bantu languages. So it cannot do tone in the way a Bantu language requires, because the syllable is the tone-bearing unit. The syllable failure and the tone failure are the same failure.