The Spanish word 'chancho' meaning 'pig' has an interesting etymology that traces back to Latin. It evolved from the Latin word 'sanctius' meaning 'sanctified' or 'holy', which first developed into the Spanish form 'sancho' (also meaning 'pig'), and then transformed into the modern form 'chancho'. The sound change from initial 's-' to 'ch-' is an example of palatalization, where the 's' sound shifted forward in the mouth to become the 'ch' sound we hear today.

The semantic shift from 'holy' to 'pig' might seem unusual, but it likely developed as an ironic or humorous euphemism, similar to how some animals are given nicknames or alternative names to avoid saying the common term.

A related Spanish word is 'sancho', an older word also meaning 'pig', which is now less common than 'chancho' in many Spanish-speaking regions. The connection between these words is clear in both their form and meaning, with 'chancho' being a phonetic variation of 'sancho'.

While there aren't direct English cognates for 'chancho', English words that share the Latin root 'sanctius' include 'saint', 'sanctify', 'sanctuary', and 'sacred'. These words all retained the original religious meaning of holiness or consecration, unlike the Spanish word which took a completely different semantic path to come to mean 'pig'.