The sense of guilt was palpable. Now there isn't enough we can do for Thumper. They become an extended part of the human circle. So too, perhaps, the farmer with his cows. The question is about the capacity for language and the presence of consciousness.
Examples oil the wheels of an argument.
You can crank along on very little oil, but oil on its own gets you nowhere. You are right to say that the first question we must ask is what is meant by 'language'. One of the fundamental marks of language is that words have 'non-natural' or conventional meanings. If I raise a hand to strike someone, that is not a statement in a language but a natural sign, just as dark clouds are a natural sign of rain. Of course, we can exploit natural signs, we can convey thoughts and meanings by leading others to make inferences from our behaviour.