take for example
The root is symbols, gestures
1 gesture+language (n) Language = sign language, which literally means "sign language".
2 road(n) road+sign, gesture = signpost, signpost is on the road, meaning "traffic sign", which is derived from: signpost = signpost, signpost = signpost.
3 signature signature +in (adv) in, within = sign in, and the signature activity refers to the "signature movement".