What term is used to describe linguistic elements that become less used and may disappear?

The chosen answer, "obsolete," refers to linguistic elements that have fallen out of use and are no longer relevant in contemporary language. This term captures the process through which certain words, phrases, or grammatical structures diminish in frequency of use to the point that they can be considered outdated or redundant.

The concept of obsolescence in language sheds light on how communication evolves, reflecting changes in society, technology, and culture. Words may become obsolete as new terms emerge to describe modern concepts or as the relevance of the original terms diminishes over time.

In contrast, commonisation refers to a process where specific words that start as proper nouns become widely used as common nouns. Semantic shift indicates a change in the meaning of a word over time rather than its overall usage. Narrowing describes the phenomenon where a term with a broad meaning becomes more specific. These terms convey different linguistic processes and do not specifically address the idea of words or phrases that entirely fade from use like "obsolete" does.