The child above was signing at age 4;10.
Watch how this child phonologically acquires the sign WORK as well as how her language develops from one word to a sentence in a time lapse.
This baby began with the "5" handshape, one of a few unmarked handshapes. Then quickly evolved to "A" and finally "S", both also other two of the unmarked handshapes.
This baby's concept of work was probably generic and pattern-based: "dad's wearing a firefighter uniform, being gone and then back; mom carrying a black workbag being gone and then back" on a regular basis.