The Spanish verb 'tardar' (meaning 'to delay' or 'to take time') comes from the Latin verb 'tardare', which also meant 'to delay'. This Latin verb was derived from the adjective 'tardus', meaning 'slow'. The evolution from Latin to Spanish maintained both the form and meaning quite closely, with just the final '-are' Latin infinitive ending changing to '-ar' in Spanish, as is typical for first conjugation verbs.

Some common related Spanish words include 'tarde' (meaning 'late' or 'afternoon'), 'tardanza' (meaning 'delay' or 'lateness'), and 'retardar' (meaning 'to delay' or 'to slow down'). All these words share the same Latin root 'tardus' and maintain connections to the concepts of slowness and delay.

In English, we find several related words borrowed from the same Latin source, including 'tardy' (meaning 'late'), 'retard' (to slow down or delay), and 'retardation'. These words all preserve the original Latin sense of slowness or delay. The connection between 'tardar' and 'tardy' is particularly easy to remember since they both relate to being late or taking too much time.