I once asked a deaf programmer how technical concepts were communicated. He explained that most non-practitioners would use finger-spelling but that a parlance among deaf programmers existed to convey a variety of technical terms. I vividly recall the sign for "Port Scanning" made by tracing an oblong ellipse oriented upwards with your index finger and then "pushing" that finger through the imaginary figure 3-4 times from the top going downwards.

I imagine a similar set of signs arising in different disciplines.