Sign language is a language, not the spoken text acted out
Aliases: ASL · Chinese Sign Language · signed English · fingerspelling
What it is
Chinese Sign Language, ASL, BSL are languages with their own grammar, space and lexicon. They are not the spoken or written words acted out one token at a time. Word-for-word systems (signed Chinese, signed English) are a different code; signers do not necessarily recognise them as their speech. Driving an avatar from captions assumes the two languages are isomorphic.
Why it happens
Sign is visuospatial. Role, time and negation often live in placement and on the face, not in spoken word order. A subject can be parked on one side of the body and retrieved by a point; questions and commands ride the brows more than a clause-final particle. Fingerspelling borrows names and words not yet in the lexicon; it is not the grammatical skeleton.
So “text → sign” aligned word-by-word yields encoding, not translation. Avatar systems typically keep the words, misuse space, and freeze the face. Native signers read that as a machine reciting. Hiring an interpreter is translating between languages. Enlarging captions into hands is not the same job.
Studying it
Have native signers of that language rate two versions: word-for-word or avatar output, versus a qualified interpreter. Score intelligibility and whether it feels like “my language.” Do not use hearing staff who learned a few signs as judges.
Independent variables: production method (word-for-word, rule-based synthesis, interpreter), whether face and space are encoded. Dependent variables: native comprehension, acceptability, judgements of “is this sign language.”
Structural comparison (order, spatial agreement, non-manuals) can explain why synthesis fails. It does not replace native review of the tape.
Where it stops holding
International Sign and fingerspelling help with names and international settings; they are not a full-language substitute. National sign languages are not mutually intelligible; an ASL track does not cover CSL users. Signed English in a classroom is a teaching tool, not community everyday language. Live interpreting sometimes slides toward the spoken order under pressure; that is the situation, not the definition of the language. Born-in-sign works with no written source are creation, not “is the transliteration faithful” — public distribution may still raise whether to translate into a spoken language.
Applying it
- When sign is required, hire a qualified interpreter. Do not ship a caption-driven avatar as the delivery. Name which sign language it is.
- The interpreter frame must show hands, face and torso, not half a hand.
- How to check: a Deaf reviewer who uses that language watches and is asked “is this my language.” Guessable words with wrong space and a flat face still fail — that was transliteration, not translation.