Shirley B. answered 12/24/24
Dedicated Tutor, for English/ESL/Math/Computer and Study Skills
Hi Daniels A.--I'm Shirley. Good Question! In my opinion, Idioms add "spice" to languages and can relate to different communities or occupations, set tone and create more expression and individuality to the way we communicate. Even standard English in the USA, vs. English written and spoken in England or as a second language in other countries, may have different idioms. Within the USA, one can tell what part of the country where someone is from--even cities! Socioeconomic, Ethnic--even businesses may have their own idioms or different uses for them, versus those used in another company.
If an idiom is a single word, it is easily placed in a sentence, following any grammatical rules. Some idioms in phrases may or may not follow strict rules, but work within a context. "Lie low" or "night owl" are 2 examples of idioms used during William Shakespeare's time--still being used in modern English.
However, the "green-eyed monster", referring to being jealous, might still be understood as jealousy, or some may think of a Dr. Seuss' character, the "Grinch" as someone being grumpy.
Knowing your audience and determining the formality or informality of the situation, whether written or oral will help decisions on what is workable. Is this for a research paper? Casual conversation? Do you, the writer or presenter, belong or are accepted as a person using certain idioms, without offending someone, or a group? Observation and experience will help with more casual and social situations. Idioms as single words or writing phrases will follow some rules, as for nouns, verbs, etc. If permitted on a project, they can also help a writer's style to stand out.