There’s a rule that makes a clear distinction between “I shall” and “I will.” However, we as speakers don’t seem to respect that line.
Do you know where that line is? Actually, here’s a better question: Did you know this rule existed?
We found out from a fourth grader.
Her teacher told her that when talking about the future, she should say “I shall” and “we shall,” but “he/she/it will,” “they will,” and “you will.”
According to Merriam-Webster’s Dictionary of English Usage, this rule goes back to the 17th century and is credited to English mathematician John Wallis. It makes a distinction between the first person and the second and third persons when expressing future tense.
Under the rule, you’d say “I shall” and “we shall,” but use “will” with he, she, it and they. If you’re talking about an obligation though, as in something you need to do or have to do, you switch it around--“I will” or “we will,” and then “shall” for he, she, it and they.
If this rule doesn’t make your grammar priority list, don’t worry. People in the 17th century didn’t really follow it either.
Merriam-Webster’s offers this conclusion:
“The traditional rules about ‘shall’ and ‘will’ do not appear to have described real usage of these words very precisely at any time, although there is no question that they do describe the usage of some people some of the time, and that they are more applicable in England than elsewhere.”
Attorneys may be quick to point out that there is an important distinction in the law, where it’s necessary to use “shall” to express obligation. That’s historically true. However, Garner’s Dictionary of Legal Usage says this distinction has little utility.
Garner writes, “‘shall’ purportedly imposes a duty,” but he sees it declining in legal use, because people see that the ambiguity is tricky. He says there’s no reason to hold on to “shall” in this context.