“Hello, how are you?” has been repeated plenty. But after that things start to vary.

In the sequence of numbers 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 7, 8, 9… Most numbers only appear once even though most numbers are a repeat.

• There are 9 possible numbers and most (88%) of them are not repeats
• "1" accounts for most (60%) of the entries in the sequence.

If we assume “hi, how are you?” is “1” and most sentences are another number, we can see how even with common phrases being repeated frequently, most sentences may tend to be original.

(I’ve not done the math and I’ve definitely not studied language enough to say how dubious or accurate the claim is, you just piqued my interest and I started trying to rationalize it all)