The Welsh language came into contact with Latin long before English did. The soldiers and colonisers of the Roman empire first arrived on the south coast of England in 55 BC (TNE #300), at a time when Britain was entirely Brittonic-Celtic speaking. Brittonic was the ancestor of Modern Welsh and Cornish, as well as of Breton (which was originally taken to Brittany from Devon and Cornwall).
This direct contact between Latin and Brittonic, which lasted until the withdrawal of the Roman occupying forces from Britain during the fifth century AD, had many linguistic consequences for the shape of the Modern Welsh language.
Modern English has borrowed very many Latin words. Hundreds of them were adopted between the 15th and 18th centuries by scholars and writers who were familiar with Classical Latin from their education.
Some Latin words had been borrowed into Old English very much earlier than that: Old English words of Latin origin included biscop “bishop” from Latin episcopus, and scrín “shrine” from Latin scrinium.
But words from Latin arrived in Welsh much earlier even than that. They were borrowed as a result of actual face-to-face interaction between Britons and ordinary Romans, rather than from any form of book-learning.
The extent to which Brittonic speakers learned Latin from the Romans living in England and Wales can be judged by the fact that about 800 different Latin words found their way into Brittonic rather early on during the contact period, with many of these words having survived in Welsh and the other modern Brittonic languages to this day.
Because of the way in which these words were learned, they tend to be of a much more mundane and concrete type than the generally rather erudite, abstract and sometimes scientific Latin loans in English. The 16th-century English borrowing aberration, from Latin aberratio “diversion”, and the 17th-century borrowing clavicle “collar bone” from Latin clavicula, can be contrasted with early Welsh porth “door, gate” from Latin porta; pont “bridge” from Latin pons (genitive pontis); and parod “ready” from Latin paratus.
The happily rather uncommon English word defenestration “the act of throwing someone out of a window”, which is derived from Latin fenestra “window”, came into English in the 17th century. Welsh ffenestr, from the same Latin source, has been the perfectly normal everyday Welsh word for “window” for over 1,500 years.
Latin barba “beard”, which survives with the same meaning in Modern Welsh as barf and in Cornish and Breton as barv, did not turn up in English until the 14th century, when it arrived, via French, in the form of barber “one who cuts beards”.
Other very everyday Welsh words which have their origins in the language of the Roman colonists of Britain include nifer “number” (Cornish and Breton niver), from Latin numerus – forms derived from numerus, such as numeral, did not arrive in English until the 1300s – and pobl “people” (Cornish pobel, Breton pobl), from Latin populus – the English word populous first appeared in 1425.
Welsh ysgrifennu “write” (Cornish scrifa, Breton skriva) came from Latin scribere, while ascribe first came into English only in the 1380s. Welsh corff “body” (Cornish and Breton korf) came from Latin corpus – English corpse did not make an appearance until the 14th century.
The original meaning of mundane was “belonging to the earthly (as opposed to heavenly) world”, from French monde, Latin mundus “world”. The contemporary meaning of “ordinary, everyday, dull” first appeared in the mid-1800s. Until a few decades ago, the word was pronounced with the stress on the first syllable.