Review Layer

The Review Layer is the safety and accountability layer for ViaSign.

It is intended to make uncertainty visible, keep human review part of the process, and prevent AI-generated signing output from being treated as automatically correct.

The Review Layer connects the grammar layer, motion layer, and community feedback process.

It exists because sign language accessibility should not only generate output.

It should generate output that can be checked, corrected, and improved.

Why a Review Layer Exists

AI systems can produce confident-looking results even when the output is wrong.

For sign language accessibility, this is risky.

A generated sign may look smooth but carry the wrong meaning.

A motion path may look natural but use the wrong signing space.

A sentence may appear understandable but miss facial expression, timing, context, or cultural meaning.

A system may produce output that looks accessible to hearing developers but feels awkward, incomplete, or inaccurate to Deaf users.

The Review Layer exists to reduce this risk.

It helps the system stay honest about what is known, what is uncertain, and what needs human review.

Review Before Confidence

ViaSign should not treat generated output as final by default.

Instead, the system should ask:

• Is this output reliable?
• Which parts are uncertain?
• Which parts are grammar-sensitive?
• Which parts depend on signing space?
• Which parts require non-manual signals?
• Which parts should be reviewed by Deaf signers or community reviewers?

This creates a review-first approach.

The goal is not to slow the work down.

The goal is to make the work safer, clearer, and more trustworthy.

What the Review Layer Checks

The Review Layer may check several parts of the system.

Grammar Review

This checks whether the sentence structure has been understood correctly.

It may include:

• question type
• negation
• time markers
• topic-comment structure
• references to people, places, or objects
• completion markers
• rhetorical question patterns

Motion Review

This checks whether motion-related output needs review.

It may include:

• movement path
• direction
• repetition
• hold
• transition
• signing space
• hand role
• placeholder motion

Non-Manual Signal Review

This checks whether meaning may depend on signals outside the hands.

It may include:

• facial expression
• eyebrow movement
• head movement
• body shift
• gaze
• timing
• mouth pattern placeholders

Cultural and Naturalness Review

This checks whether the output feels natural, respectful, and appropriate.

It may include:

• whether the phrasing matches real signing use
• whether the output feels awkward or unnatural
• whether the sign choice needs community review
• whether the system is overconfident
• whether the output may misrepresent the language

Review Flags

Review flags are markers that show when output should not be treated as final.

A review flag may be attached to:

• a sentence
• a grammar pattern
• a sign choice
• a motion instruction
• a non-manual signal
• a whole generated output

Examples of review flag types may include:

• review_required
• motion_uncertain
• nms_required
• space_reference_needed
• community_review_needed
• grammar_sensitive
• placeholder_output
• low_confidence

These labels are not final. They are examples of how the system may make uncertainty visible.

Relationship to Parser V2

Parser V2 can identify grammar patterns and review-sensitive structures.

For example:

• a question may require facial expression review
• negation may require non-manual signal review
• a directional action may require signing space review
• a topic-comment structure may require grammar review
• a sentence with unclear references may require human review

Parser V2 does not solve all of these by itself.

It helps mark where review may be needed.

Relationship to the Motion Engine

The Motion Engine can generate motion-ready instructions.

The Review Layer helps check whether those motion decisions are safe to present.

For example:

• Is the movement path only a placeholder?
• Is the direction meaningful?
• Does the motion depend on established signing space?
• Does the motion need review led by Deaf community members?
• Does the animation look smooth but remain linguistically uncertain?

This is important because motion can create false confidence.

A polished movement may look finished even when it still needs review.

Deaf Community-Led Review

The Review Layer should support feedback led by Deaf community reviewers.

This means review should not be treated as a final checkbox after the system is complete.

It should be part of the process.

Deaf reviewers, signers, teachers, and community members may notice things that a technical system cannot.

They may notice whether output feels natural.

They may notice whether timing is wrong.

They may notice whether the grammar is awkward.

They may notice whether the system is flattening the language.

They may notice whether a generated output is technically close but still not right.

That feedback is not a weakness in the system.

It is part of how the system becomes safer and better.

What the Review Layer Is Not

The Review Layer is not a replacement for Deaf community review.

It is not a guarantee that output is correct.

It is not a final authority on Singapore Sign Language.

It is not a way to avoid human judgement.

It is a structure for making review visible, organized, and easier to act on.

Possible Review Flow

A possible review flow may look like this:

1. Input sentence
2. Parser V2 analysis
3. Grammar and structure signals
4. Initial review flags
5. Motion Engine planning
6. Motion-specific review flags
7. Generated draft output
8. Human or community review
9. Corrections and notes
10. Updated system rules or documentation

This keeps the system auditable.

It also allows mistakes to become learning points instead of hidden failures.

Guiding Principle

The Review Layer exists because accessibility technology should be accountable.

It should not only produce output.

It should show what needs care.

It should not hide uncertainty.

It should make uncertainty visible.

It should not treat Deaf users as the final audience only.

It should include review led by Deaf community members as part of the process.

For ViaSign, review is not an obstacle to building.

Review is part of building.