How does the Greek 'legein' relate to PIE *leg 'to collect'?

Question

ENTRY: leg-
DEFINITION: To collect; with derivatives meaning “to speak.” Oldest form *le-, becoming *leg- in centum languages.
[...]
3. lexicon, logion, –logue, –logy; alexia, analects, anthology, catalog, dialect, dialogue, dyslexia, eclectic, eclogite, eclogue, horologe, lectotype, prolegomenon, from Greek legein, to gather, speak, with o-grade derivative logos, a gathering, speech (see also 6 below for derivatives independently built to logos).

Initially, I was researching the etymology of the suffix -logy.
What connects the Greek legein with the PIE root leg-?

My guess is this: In Ancient Greek, if one wanted to speak to many people, then these people must be gathered together. I doubt my guess, because I am unsure if the sense of collection refers to some historical particularity of speech, such as the collection of certain rhetoric. My doubt is worsened by my former ignorance of early ways of reading, when I asked this question on ELU.

Answer 1

The basic meaning of the root *leǵ- was "pick out". Compare e.g., from Latin, se-lect, col-lect: to collect things is to pick them out (legō) and place them together (con-). In Greek, the development seems to have been something like "pick out (information)" > "recount" > "say". If you're telling someone a story, you start by picking out the things you want to tell them. The semantic relationship is possibly a bit clearer if you think about the noun from the same root logos, which means "verbal account": an account is a collection of information that the speaker has picked out for some communicative purpose.

(The reddit thread quoted in your answer is a bit misleading in that in Greek, unlike in Latin, legō hardly ever means "read", while in Latin it doesn't mean "say": the developments in the two languages were not the same, though both senses start from the idea of "picking out".)

Answer 2

I quote from https://redd.it/6k9usb that answers this question.

razlem. 61 points 3 years ago.

The semantic shift isn't that big: reading something = gathering information. Even in English you have "I reckon" being interchangeable with "I gather".

AllanBz comments on How did 'putare' evolve to include all these meanings?

A similar thing happened with Greek logos, thought, word, etc. Lego originally meant "gather." It is cognate with legere and legio (legion), a "levy," and collect (which is also used metaphorically, to recollect is to remember). A similar metaphorical construction is used today with gather: "I gather she will not join us tonight."