"Language" in the sense of "the thing only humans have been shown to do" requires a bit more than just one to one correlations between signifiers and objects (or a "sentence" of signifiers with the same meaning as all of the words added together independently). For a system of symbols to be "language" there must be a difference between "what the cat ate" and "what ate the cat". No animal communication has been shown to have a grammar to it, and thus the ability to express exponentially many unique ideas with each additional word.
I feel like there are human languages where the symbolic distinction between "what the cat ate" and "what ate the cat" are nil and the understanding is achieved contextually.
Is there a grammar? ie. a set of rules to form valid sentences in the language
Is there linguistic creativity? ie. you can generate new words to describe things never encountered
Is there metalinguistic reflexion? ie. can you use the language to talk about the language itself?
Can the language allow displacement? i.e. talking about things that are not in the current spacetime point
These are some of the core requirements for a system of communication to be considered a language.