Complex sentence: Speech generating devices (SGDs) have their roots in early electronic communication aids, the first of which was a sip-and-puff typewriter controller named the Patient Operated Selector Mechanism (POSM or POSSUM) prototyped by Reg Maling in the United Kingdom in 1960.
Split into simpler sentences: Speech generating devices (SGDs) have their roots in early electronic communication aids. The first such aid was a sip-and-puff typewriter controller named the Patient Operated Selector Mechanism (POSSUM) prototyped by Reg Maling in the United Kingdom in 1960.