There are many foreign words and phrases in current English. As the world’s most flexible and widely used language, English constantly adopts new words from elsewhere. In particular, the flow of words from French has not stopped since the Norman invasion.
Many words and phrases taken from Greek and Latin are still used by some people. But fewer and fewer readers are familiar with this vocabulary, so there is a strong case for finding English equivalents. An obvious expression is annus horribilis, a phrase used by the Queen in 1992 and since repeated ad nauseam by all and sundry.
Use words of foreign origin accurately but not pretentiously, always asking yourself: ‘Will my reader understand this?’ ...