The Spanish verb 'tocar' (meaning 'to touch' or 'to play an instrument') has an interesting onomatopoeic origin. It comes from the sound 'toc', which represents the sound of knocking or tapping. The verb was formed by adding the Spanish infinitive suffix '-ar' to this sound-based root. This is a great example of how languages can create words that directly imitate the sounds they represent.

The evolution from a knocking sound to meanings like 'touch' and 'play an instrument' makes intuitive sense - when you touch something or play an instrument, you often make contact in a way similar to a tapping or knocking motion.

Some related Spanish words include 'toque' (a touch or ring), 'tocador' (dressing table/vanity), and 'tocadiscos' (record player). All these words share the basic idea of contact or touching from the root 'toc-'.

While English 'touch' might seem related to Spanish 'tocar', they actually have different etymological origins. 'Touch' comes from Old French 'touchier', while 'tocar' comes from the sound of knocking. However, English does have some onomatopoeic words like 'tick-tock' that similarly imitate percussion sounds, though they're not directly related to 'tocar'.