Language is most usefully defined as a rule‑governed system of symbols that humans use to communicate and make meaning, typically through speech, writing, or signing.wikipedia+2
In linguistics, language is often described as a structured system of communication with grammar and vocabulary, allowing speakers to produce and understand an unbounded number of new sentences (productivity) and refer to things beyond the here‑and‑now (displacement). It is a socially shared, conventional code: a community agrees, implicitly, on which sounds or signs count as words and how they can be combined. Major reference works also emphasize that language can be spoken, written, or signed (e.g., American Sign Language) and that each individual language (like English or Korean) instantiates the more abstract human capacity for language.britannica+2
More concise dictionary-style formulations include: “a system of communication consisting of sounds, words, and grammar” or, more broadly, “a system of conventional spoken, manual (signed), or written symbols by means of which human beings, as members of a social group and participants in its culture, express themselves.”dictionary.cambridge+2