The Spanish word 'muy' (meaning 'very') comes from the Latin word 'multum' meaning 'much'. The evolution from Latin to modern Spanish went through Old Spanish forms 'muito' and 'muit'. Over time, the word underwent phonetic simplification, dropping the final 't' and shifting its meaning slightly from 'much' to become the modern Spanish intensifier 'muy' meaning 'very'.

The Spanish word 'mucho' (meaning 'much' or 'many') is a close relative of 'muy', as they both derive from the same Latin root 'multum'. While 'muy' evolved to become an intensifier meaning 'very', 'mucho' retained the original quantitative meaning of 'much/many'.

While English 'much' and Spanish 'muy' may look different, they are actually distant cousins! Both can be traced back to similar Proto-Indo-European roots, though they evolved through different paths. The English word 'multi-' (as in 'multiple', 'multiply', 'multitude') is even more closely related, as it comes directly from Latin 'multus/multum', the same source as Spanish 'muy'.