Triple Threat

All in all, irregular verbs notwithstanding, English has a pretty simple rule for forming the past tense: tack "-ed" onto the end of the bare infinitive. There are sub-rules for spelling; if the verb ends in (or is) consonant-vowel-consonant, double the last letter, and if it ends with an "-e", drop that letter before adding the suffix. But otherwise, it's not too hard to form the past tense of most verbs.

Some verbs, however, are harder to handle. Those ending in "-ead" are remarkably irregular; there are three patterns for forming the past tense, and as usual there's no way of telling which is which--you just have to learn them. (Luckily, there aren't too many of these verbs.) One pattern is the usual one, suffixing "-ed" ("bead", "thread"). Another is to drop the "-a" ("lead"--the one that rhymes with "bead"). The third is to leave the verb alone entirely: sometimes this changes the pronunciation ("read"), and sometimes it doesn't ("spread"). "Read" is an especially mean and ironic trick for the language to play on people who are reading aloud; the sentence in which it appears as a past participle might contain no indication of being in the past tense ("I read to my daughter every night"), leaving the reader to flounder around elsewhere in the paragraph for clues.

There's one verb in English that has three past-tense forms, and it uses all three of these patterns: "plead", which lays claim to "pleaded", "pled", and "plead" (short "-e-", just like past-tense "read").