10 sign languages · 158 signs

learn to sign.
your camera checks.

signLingo watches both of your hands in real time and tells you exactly which finger to move. Not a video you copy — a coach that answers back.

Free. No account. Video never leaves your device.

Live, on this page

don’t take our word for it

This is the same recogniser the lessons use, running against the full ASL alphabet.

try it right here

Turn on your camera and fingerspell. Nothing is uploaded — the model runs inside this tab.

You spelled

Hold a letter steady for half a second and it lands here.

The closest matching handshape and how to make it will show here.

Matching all 26 ASL letters at once, from 21 landmarks per hand. Two hands are tracked for the languages that need them.

how the checking works

  1. 01

    twenty-one points, per hand

    A WebAssembly model finds the wrist, every knuckle and every fingertip, thirty times a second — in 3D, on both hands at once.

  2. 02

    geometry, not guesswork

    Each sign is written as constraints: index straight, pinky curled, thumb out to the side, these two tips touching. Scoring them is how the app can say which finger is wrong instead of just “no”.

  3. 03

    held, not flashed

    A shape has to hold above the confidence line for half a second before it counts, so passing through the right pose on the way somewhere else doesn’t earn you a letter.

A
L
V
Y
C
W

Every diagram in the app is generated from the same constraints the recogniser grades against, so the picture can never drift from the answer.

why this is worth building

Most people who could sign never learn, because practising alone means never knowing whether you got it right. A camera can answer that question, on any laptop, for free.

1.5B
people live with some degree of hearing loss
70M
deaf people use a sign language as their first language
300+
distinct sign languages are in use worldwide
90%
of deaf children are born to hearing parents who don’t yet sign

Figures from the World Health Organization and the World Federation of the Deaf.

what this does and doesn’t teach

It does

  • Grade handshapes from both hands, in real time, offline.
  • Name the specific finger that’s wrong, not just mark it wrong.
  • Cover ten sign languages, including two-handed alphabets.
  • Tell you when a sign it graded also needs movement it can’t see.

It doesn’t

  • Teach grammar, which in sign languages lives in movement and face.
  • Replace a Deaf teacher, or a Deaf community to sign with.
  • Cover full vocabularies — fingerspelling is a doorway, not the room.
  • Claim that signing at a laptop is the same as signing with a person.

your first letter is ninety seconds away

Start signing