If you are around my age, you were probably taught the shall/will distinction in English class. For those of more recent vintage, let me explain this curiosity of usage.
Shall, we were instructed, is proper for first person singular and plural, will for second and third. I shall look into it. Shall we dance? You will note the distinction. He, she, and they will observe it.
But there were exceptions. Will was to be used in the first person for particularly emphatic statements, as in the dying Samuel Johnson's "I will be conquered. I will not capitulate." Similarly, shall could be used for emphatic statements in the second and third persons, as in the French shouting "They shall not pass" at Verdun.
Good little teacher's pet that I was, I learned all the rules and often talked like a book.
But in time, I noticed that my teachers, including my English teachers, did not observe the shall/will distinction themselves when they spoke.
The reason, as Bryan Garner explains in Garner's Modern English Usage, is that "with only minor exceptions, will has become the universal word to express futurity, regardless of whether the subject is first, second, or third person." He lists the two major exceptions: (1) interrogatives (that Shall we dance?) and (2) legal documents "in which shall purportedly imposes a duty."
Mr. Garner also quotes Gustave Arlt of the University of California from the late 1940s: "The artificial distinction between shall and will to designate futurity is a superstition that has neither a basis in historical grammar nor the sound sanction of universal usage. It is a nineteenth-century affectation … certain grammarians have tried hard to establish and perpetuate."
Merriam-Webster's Dictionary of English Usage has a lengthy entry on shall and will, with some hints at the origin of the distinction. In the fourteenth century, schools used will to translate the Latin volo, and shall, which had no exact Latin cognate, was used for the future tense. John Wycliffe followed that pattern in translating the Bible, so that the school tradition and the profound influence of the English Bible kept shall in circulation.
While shall remains more or less common in British English, it is vestigial in North America, Scotland, and Ireland, largely supplanted by will. So at the time that I was diligently internalizing this supposed rule, it was already a dead letter.
As Rosemarie Ostler points out in her excellent Founding Grammars, the grammarians of the eighteenth and nineteenth centuries freely copied from one another. Textbooks follow the same pattern, which is how my English textbooks in the 1960s parroted nineteen-century superstitions exploded decades previously. And those of you who follow these posts have seen how much prodding is required to get the Associated Press Stylebook to examine its mossback prescriptions and pay attention to "the sound sanction of universal usage."
My enterprise here over the past decade and more has been to encourage my readers, particularly my fellow journalists, to tread the same path I have followed, examining the things I have been taught to see how much is sound doctrine and to discard the rubbish.
Shall I go on?