It only has to be able to express abstract ideas, with a power at least close to ours. Presumably, we are not going to communicate with alien species unless they have a sufficiently developed science and technology, and it is hard to imagine that without a language.
And by “a language like ours”, do you mean English? (The one language that we know you and I both have in common.) Noam Chomsky has spent a career looking for a common deep grammar for all human language, and it turns out that there is not much in common, except at the most fundamental and abstract level. Despite this, there are no human populations divided by having mutually incomprehensible languages, and maybe that is so throughout the galaxy.
And by “a language like ours”, do you mean English? (The one language that we know you and I both have in common.) Noam Chomsky has spent a career looking for a common deep grammar for all human language, and it turns out that there is not much in common, except at the most fundamental and abstract level. Despite this, there are no human populations divided by having mutually incomprehensible languages, and maybe that is so throughout the galaxy.