ELI5: Explain Like I'm 5

Grammaticalization

Grammaticalization is when a word or part of a word changes its function and becomes part of the grammar of a language.

Let's imagine you have a toy set with different pieces - a square, a rectangle, and a triangle. Each piece has a different function, but what if you could take the rectangle piece and use it as part of the square piece to create a new toy? This is kind of like what happens in languages when a word or part of a word is "re-purposed" to have a new function in grammar.

For example, let's say you have the word "will". Originally, it was used as a verb meaning "to desire", such as "I will have pizza for dinner." But over time, it started to be used more as an auxiliary verb to indicate future tense, as in "I will eat pizza for dinner tomorrow." The word "will" has become grammaticalized - it has taken on a new function within the language, helping us to express time and certainty.

Another example is the word "going to". Originally, it was used as a way to talk about physical movement, as in "I am going to the store." But over time, it started to be used more as a way to express future plans, as in "I'm going to eat pizza for dinner tonight." "Going to" has become grammaticalized - it has taken on a new function within the language, helping us to express future intentions.

So, grammaticalization is when words or parts of words start to be used in new ways to help us express different functions in language. It's like taking a toy piece and using it in a new way to create something different and new.