Only if we are being extremely literal.
Cinema is a form of expression, text, etc. you use it to "speak", edits, shots down to blocking, cinematography, etc. are your words and compose your text.
Your objection may rest upon the fact that there is no "language council" like most countries have, and that as such there are no formal rules per language - but we can still look at cinematic conventions, norms per genre, country, type, etc. and as such speak of the language of horror films. Most conventional films build on a more established language, with easily understood text, while more creative works play with cinematic language in a different way.
By cinematic language, I am broadly referring to all the tools a filmmaker has, all the elements that are not strictly narrative, i.e. the text that is not text. The way a film is told, not the way it is written.