the word 'teachable' is a modern english formation built upon the old english verb 'teach'. the core verb 'teach' itself originates from the proto-germanic taikijan, meaning 'to show', which is rooted in the proto-indo-european deik-, meaning 'to show, point out'. this ancient sense of pointing out or demonstrating evolved into the concept of instruction. in the late middle english period, the productive latin-derived suffix '-able', meaning 'capable of', was appended to the native verb. the resulting compound 'teachable' literally means 'capable of being taught or instructed', applying both to a receptive learner and to a subject amenable to instruction.

Structure: teach + able teach (from old english tǣcan, meaning 'to show, instruct') + able (from latin -abilis, a suffix forming adjectives meaning 'capable of, fit for').