While reading an otherwise well-written and well-edited book, I was bemused to note that the number of high school students in the United States had “lept” from one total to another over a given span of years. How was it, I wondered, that the fact that lept is not a word escape a writer, a developmental editor, a copy editor, and a proofreader (assuming that the manuscript benefited from perusal by each of these agents) — not to mention a spell-checking program?
It’s easy enough for a writer to be mistaken about the validity of such a word. Leapt is a variant of leaped (more commonly used in British English than in American English, but gaining in popularity on this side of the Pond), but the writer can be forgiven for assuming that just as the past tense of creep is crept and those of keep, sleep, sweep, and weep are kept, slept, swept, and wept, leap takes a past-tense leap to lept. (Creeped is not a word, except informally to refer to being creeped out, the sensation of being disturbed by someone or something thought to be creepy, and keeped, sleeped, sweeped, and weeped are likewise nonwords, though the last two mutations sometimes sneak past editors.)
A moment’s thought, however, will make it clear to the writer that this progression (or is it a regression?) is not universal: The past-tense forms of beep, peep, and seep are beeped, peeped, and seeped, rather than bept, pept, and sept. (That last word is valid as a noun meaning “clan” or “branch of a family.”) More significantly, though, words identical to leap in spelling as well as sound form past tenses of heaped and reaped, not hept and rept.
English is full of challenging inconsistencies of spelling and pronunciation: Compare the present and past tenses of read — identical in appearance but not in sound — and note the difference in tense transformation for head (headed) and lead (led), not to mention the fact that the present-tense forms are pronounced differently.
These idiosyncrasies make it all the more important for even native speakers and writers — including those with decades of experience — to consider the consequences of less-than-stringent vigilance: Nobody else may notice your mistake, either — until I pick up the published book and write a post about it.
To help you maintain a high standard of diligence, remember this hypothetical penalty (one that I should post a notice about in my office): Pretend that spelling and other mechanical errors are a capital crime, and see what this imaginary impetus does for your motivation to avoid them.