Sometimes words get shorter because people who use them start to leave out sounds or syllables. Take, for example, “pacifist.” Around the turn of the 20th century the word was “pacificist,” as used in the March 4, 1907 edition of the London Times: “Sir H. Campbell-Bannerman’s article…on the limitation of armaments…cannot be said to have made a favourable impression except among the Socialists and the ‘Pacificists’.” And in fact “pacificist” hasn’t entirely gone away; this is from the Journal of Modern History in 1997: “ The Bolsheviks were never pacificists. They were quite simply not strong enough to fight an offensive.”
Interestingly enough, the “pacifist” form existed at the same time; “The French ‘Pacifists’ will appeal to England’s example in order to induce France also to cut down her naval programme” is from the same London Times in 1906. The shorter, easier to say (and spell) version has always been more widely used.
The process of shortening a spoken word by omitting sounds or syllables is called “haplology” (a word that might benefit from itself, now that I think of it). It particularly applies, in English, to repeated sounds. So for example, applying haplology to “haplology” would yield “haplogy,” which seems like an improvement. It usually starts as either a convenience, a mistake, or a dialect. If you skip over the middle of “February” and say “Febry,” whether because you’re in a rush or because you’ve always thought “February” is a silly name for a month and too hard to say and spell anyway, you’re a hapless haplologist.
In the case of “pacificist” losing out to “pacifist,” though, there’s another process going on because the writing of the word also differs. When that happens, it’s “haplography.” It’s occasionally a mistake, but comparatively rare compared to the spoken version. But there’s a more general version of this used poetically, as in using “o’er” for “over” or “e’en” for “even.” The more general version, in linguistics, is called “syncopation” (you know, “sync’n”).
It’s also worth noting that the reverse process — words getting longer — doesn’t seem to exist. There are a few words with longer versions that (confusingly) mean the same thing, like “flammable” and “inflammable,” but there doesn’t seem to be any case where the longer version has displaced the shorter one. And in just about every case where there’s a longer version of a word, it’s either formed by adding a prefix or suffix, or the longer version is in fact the older, original word. Shorter versions of words are much more likely than their longer siblings to get popular. There are several related to transportation: “bus,” “taxi,” “van,” and (at least in England) “pram” are all shortened versions. “Exam,” “lab,” “fridge,” “phone,” and “burger” have all been haplologically altered as well. There are a couple of less well-known ones, too. “Mob” is a short version of the Latin phrase “mobile vulgus,” which means “a fickle crowd.” “Goodbye” was originally “God be with you,” and “hello” was, all the way back in Old English, “whole be thou.”
Even the word “lord” used to be something longer, although you have to go all the way back to Old English to find “hlāfweard.” That’s a sort of Old English compound word; “hlaf” means loaf, as in bread, and “weard” is a steward — sort of a“bread distributor;” the one who provides the bread. Even today the “lord” of a household is sometimes called the “bread winner.” Everybody else in a household or tribe was a “hlāfǣta”, a “bread eater.”
And speaking of Old English, haplology operated back then as well. Having an “f” sound at the end of a syllable wasn’t unusual, but one of the widespread changes that turned Old English into Middle English was that the middle “f” disappeared, along with the “w” sound, leaving “hleard” (more or less), the word that eventually became “lord” in English and “laird” in Scottish.
The hlāfweard, of course, handed out more to eat than just bread. Fruit, for example. They didn’t have any of these in England back then, but think of the haplology possibilities for “bananas.”
