Letters that simply intrude into our words

Last week's researches into the "wards" words – who says "toward" and who says "towards," and why – led me down a path with the exotic-sounding name of "epenthesis." Deadlines called me back before I could do much exploring, but this week I've returned to this particular part of the enchanted forest that is language.

Epenthesis is, simply, the insertion of a vowel or consonant into a word to make it easier to pronounce. The word comes from Greek and has the same rhythm as another Greek-derived term, hypothesis.

When Yogi Bear talks about swiping "pick-a-nick" baskets in Jellystone Park, it sounds as if he's just having fun, but he's also demonstrating "epenthesis," inserting a vowel to avoid the consonants bumping up against each other. The "a" sound people insert in "Realtor" is another familiar example.

Epenthesis occurs especially in combinations involving nasal sounds – "m" and "n" – with what phoneticians call "fricatives" – sounds made by pushing air out through a small space between your teeth and tongue or lips, such as "f," "z," and "th."

Can you pronounce hamster or warmth without putting a "p" in them? Can you pronounce incidence differently from incidents? I've been trying, and I haven't succeeded, though I can see that only one is actually spelled with a "t."

Sometimes the "intrusive" letter makes itself so completely at home that it gets adopted into the spelling. The "b" in words such as humble, mumble, and nimble, is epenthetic – not there in the root words from which they grew. So is the "d" in thunder.

The surname "Thompson" is regarded as a variant of "Thomson," obviously "son of Thom," or Tom. But a Google search of "Thompson" just now has brought up 376 million hits, compared with 187 million hits for "Thomson," even though news from Thomson Reuters is ubiquitous on the Web.

If some words pick up extra sounds for the sake of ease of pronunciation, however, other words lose them, and eventually that loss may be reflected in the spelling. Vunerable is already out there on the Web, albeit in small numbers, despite Google's efforts to redirect searchers to the proper form, which still has its "l." I heard from a reader the other day complaining that vulnerable seldom gets that "l" in its initial syllable when spoken aloud over the public airwaves, let alone in ordinary social conversation. I commiserate with her, in part because I never want to give up on an English word that is pronounced more or less as it's spelled.

But my research into epenthesis makes me appreciate that unfamiliar sounds are hard to get right. Part of the problem with nuclear, for instance, is that no other familiar words follow the same pattern. "Nucular" may be cringeworthy, but it at least follows a pattern we know from words like muscular and binocular.

Simply Googling the letters "uln" suggests that this letter combination appears mainly in medical terminology: The Latinate ulna and ulnar refer to the human elbow.

To pronounce vulnerable properly, getting the liquid "l" in there and following it with the "n" – another "liquid" – you have to slow down like a military convoy negotiating the twisting, winding road through a mountain pass. Vulnerable is not a word that can be pronounced quickly. It's not a one- or two-punch word you can blurt out in an argument. You have to make yourself vulnerable, in a sense, to say the word. And there's a certain poetry to that.