The Spanish verb 'doblar' comes from the Latin verb 'duplare' meaning 'to double'. This Latin verb was formed by combining the adjective 'duplus' (meaning 'double') with the verbal suffix '-are'. As the word evolved from Latin to Spanish, the 'pl' sound shifted to 'bl', and the 'u' became 'o', giving us the modern Spanish form 'doblar', which means 'to fold' or 'to double'.

Some related Spanish words include 'doble' (double), 'duplicar' (to duplicate), and 'doblegar' (to bend, to subdue). All these words share the same Latin root 'duplus' and relate to the concepts of doubling, folding, or bending.

English speakers can connect 'doblar' to several familiar English words that come from the same Latin root 'duplus', such as 'double', 'duplicate', and 'duplex'. The connection between folding (doblar) and doubling (double) makes intuitive sense - when you fold something, you're essentially doubling it over itself.