I don't have enough linguistic background to understand the distinction, but I've also heard that using "will" for "intent to do something in the future" is somehow linguistically unusual because previously that job was used by "shall".
Sorry I can't give more details, I forget what the actual distinction between the two is. I just recall that it apparently creates difficulty when English speakers learn Romance languages that still have their equivalent of "shall".
Edit:
Apparently, the distinction can either be a lot more relevant or a lot less relevant than I thought depending on the context (e.g. legal text vs. everyday speech).
It's interesting how much of language is invisible to a native speaker. If you had asked me, I would have said that most people never use "shall". However, now that the article points it out, I realize that native speakers use "Shall we <verb>" all the time.
"will" used to mean "to want", like its cognates in Dutch or German still do. However, it's not really unusual, it's quite common for desiderative forms of verbs to evolve into expressing a future tense, something similar happened independently in a few Indo-European language families, like Greek, Albanian, Celtic etc...
Sorry I can't give more details, I forget what the actual distinction between the two is. I just recall that it apparently creates difficulty when English speakers learn Romance languages that still have their equivalent of "shall".
Edit:
Apparently, the distinction can either be a lot more relevant or a lot less relevant than I thought depending on the context (e.g. legal text vs. everyday speech).
https://en.wikipedia.org/wiki/Shall_and_will
It's interesting how much of language is invisible to a native speaker. If you had asked me, I would have said that most people never use "shall". However, now that the article points it out, I realize that native speakers use "Shall we <verb>" all the time.