The vs An (Comparing for most appropriate.)

Question

The average person knows 25000 words.

Vs

An average person knows 25000 words.

I find the latter more appropriate, but the former is what I read almost everywhere. Does anyone have a coherent explanation to which one is more correct?

Answer 1

The average speaker knows 25000 words.

An average speaker knows 25000 words.

Both are ways of making a generalization.

The average speaker refers to the prototypical average speaker.

An average speaker refers to a speaker selected at random, as it were, from the set of average speakers, a representative sample.