The Gemara uses a phrase that occurs 20 times in Shas:

אֲמַר לֵיהּ: לָא שְׁמִיעַ לִי, כְּלוֹמַר לָא סְבִירָא לִי.

He said to him: I did not hear about this statement; that is to say, I do not hold in accordance with it. 

I would say, the best translation is “I did not hear of this”, and then the Gemara’s narrator interjects, “That is to say, he does not agree with it.”

It is a meaningful phrase, that indicates a certain humility and gentleness. That is to say, when the sage disagreed instead of declaring outright, “You are wrong”, or even “I do not agree”, he simply says, “This matter I do not hear”.  The implication is there is a possibility that it is not a disagreement, but only a lack of fully understanding the other person’s argument.  Of course, since often the person making the statement is a sage of superior authority, it is also a humble way of signalling, “Maybe YOU did not hear correctly.”  

In relationships we say we disagree much more than we say we didn’t hear it right or do not understand. I think this Gemara phrase is teaching proper Middos and communication skills.