# audio-visual isomorphism

Audio-visual isomorphism is the notion that spoken and written Lojban should be the same (have a one-to-one mapping).
• jezrax:
"Isomorphism" is a strong word. It requires not only that no information be lost in converting from writing to speech or the other way, but also that no information be gained. The two must be structurally identical, and therefore functionally identical (from a mathematical point of view) as well.

## Breakdowns of audiovisual isomorphism

It's not strictly true that in Lojban spoken and written utterances are structurally identical. Minor, avoidable breakdowns of audiovisual isomorphism are possible. "Minor" means they're unlikely to confuse humans, though they may confuse stupid computer programs. "Avoidable" means you can speak and write so that the breakdowns do not occur.

• The reference grammar (chapter 19 section 10) mentions that zoi quotation is an example of breakdown. A guard word that can safely delimit text may not be safe in speech, and vice versa.
• mudri:
Also, there's no telling how to spell/pronounce the contents of a zoi quotation.
• Some people may write both to and vei as (, leading to ambiguity in whether the parenthesis is the start of a parenthetical comment or a mathematical expression. The same obviously goes for the right parenthesis. (But writing this way is not common practice).
• this is avoidable ... by using to and vei. Obviously things can start to breakdown if you don't follow the rules. It doesn't really seem worth mentioning, certainly not as evidence that there are breakdowns in Lojban's audiovisual isomorphism.
• Since not all pauses are written, even when mandatory spoken, that is a breakdown.
• jezrax:
The pause does not have to be written . to be represented in the text. When I write mi'e jezrax instead of mi'e .jezrax., it's unambiguous from the word spacing that jezrax is a cmene (name) not preceded by la or doi and must be surrounded with pauses. So no information is lost in writing.
• Lojban text does not mark for stress. An unambiguous orthography (which is what we have, stress-wise) is not the same as an isomorphic one.
• jezrax:
It is not a breakdown. Similarly to pauses, the information represented by stress in speech is usually represented as word breaks in writing. I don't see any information gained or lost either way, though it's true the system is complicated and it's hard to be completely sure. See Word Resolution Algorithm.