I could think of a language as just being a mapping from symbols to propositions, in which case any variation in propositions expressed means that it is not the same language.
If that’s what counts as a language, I think we should deny the existence of languages:
“Rather than take for granite that Ace talks straight, a listener must be on guard for an occasional entre nous and me...or a long face no see. In a roustabout way, he will maneuver until he selects the ideal phrase for the situation, hitting the nail right on the thumb. The careful conversationalist might try to mix it up with him in a baffle of wits. In quest of this pinochle of success, I have often wrecked my brain for a clowning achievement, but Ace’s chickens always come home to roast. From time to time, Ace will, in a jersksome way, monotonise the conversation with witticisms too humorous to mention. It’s high noon someone beat him at his own game, but I have never done it; cross my eyes and hope to die, he always wins thumbs down.” From A Nice Derangement of Epitaphs
If that’s what counts as a language, I think we should deny the existence of languages:
“Rather than take for granite that Ace talks straight, a listener must be on guard for an occasional entre nous and me...or a long face no see. In a roustabout way, he will maneuver until he selects the ideal phrase for the situation, hitting the nail right on the thumb. The careful conversationalist might try to mix it up with him in a baffle of wits. In quest of this pinochle of success, I have often wrecked my brain for a clowning achievement, but Ace’s chickens always come home to roast. From time to time, Ace will, in a jersksome way, monotonise the conversation with witticisms too humorous to mention. It’s high noon someone beat him at his own game, but I have never done it; cross my eyes and hope to die, he always wins thumbs down.” From A Nice Derangement of Epitaphs