Language is reflexive. It formats the reality out of which it’s “created”. It shapes and enframes thoughts of people who use it. It’s the transcendental horizon, the “frame”, the “format”/“form” of reality and thoughts. I would even risk introducing a concept from music theory here - language is the texture of being and thinking. Here a Kantian lesson is - instead of seeking and prioritizing the “hidden reality” beneath all phenomena perceived by finite and limited senses (which is the attitude taken by empiricism, pragmatism, and modern science), we elevate the obstacle to the “reality-in-itself” - the forms of mind - as “constructors” of the (phenomenal) reality (which is the stance taken by constructivism, and a few computer scientists specialized in programming languages). Those who view languages as mere tools for their ultimate purposes/contents/meta-languages (say, seeking some theoretical reality in a specific field, like Mathematics, Physics, Economics, Machine Learning, etc.) overlooked the reflexive power of form.
Here a Hegelian style sentence can sum all up: form as the most particular content gains its universality (form vs. content, particularity vs. universality). Language as form thus plays a crucial role in all symbolic activities, from daily communications to scientific research, from “natural language” to computer/programming languages. Language as form acts like a specter, a surplus, a by-product, and an effect. In an even more radical way to put it, there is no meta-language, and every purpose is already a surplus (vice versa!); there is no immediate reality, and every content has to be mediated by language as form.