This is the same as saying that words have no meaning! Under this mental framework why would it be wrong to say that every living human can speak fluent french?
How would you even know which language anyone is speaking?
Counterproposal: words are a tool for communication and meaning is something we gather from the communication. In this words are no different than hand gestures, facial expressions, and body language.
The parties to a communication can only communicate effectively if they agree enough on the meaning of words/gestures/expressions/actions (which is why we cannot speak a language we do not know)
> which is why we cannot speak a language we do not know
You can, however, speak a language you do know even when the listener doesn't know said language. Thus proving that the words spoken are defined by the speaker. It must be that way, fundamentally – as you suggest, you can only speak the language you know. If that tells that words have no meaning, sure. That assertion means nothing anyway.
My main issue with either "the speaker defines the meaning of words" and "the listener defines the meaning of words" is the resulting definition is useless for all practical and theoretical concerns. It is a meaningless meaning of the word meaning.
What they are trying to say is
"the speaker defines the meaning of words" -> everybody understand things differently and there is no external absolute authority of meaning
and
"the listener defines the meaning of words" -> people are going to understand their interpretation of what you say, not what you mean
Both are useful and important statement people can learn from while "X defines the meaning of words" is meaningless.
The listener is only a consumer. It cannot define the words. It is not responsible for their use. It interprets, and to be sure misinterprets, the words, but that, while similar, is subtly different.
Of course, at this point we're ultimately getting stuck in that nerd thing I spoke of in another comment: "I know the tech crowd in particular loves to make up their own pet definitions for words and then double down on refusing to acknowledge that any other definition is possible, thereby continually talking past each other because there is no shared lexicon to hilarious effect, but that's not the norm, thankfully."
So, while hilarious, I will break the cycle and ask you to clarify what you mean by "define" so that I can shift to using your definition. I'd have used it from the start but I haven't quite figured out how to read your mind yet, so I as the speaker, unfortunately, was beholden to defining it as I understand it.
How would you even know which language anyone is speaking?
Counterproposal: words are a tool for communication and meaning is something we gather from the communication. In this words are no different than hand gestures, facial expressions, and body language.
The parties to a communication can only communicate effectively if they agree enough on the meaning of words/gestures/expressions/actions (which is why we cannot speak a language we do not know)