Maureen Koplow, responded to my comments on the word benight, with a three part question, one part philosophical, the other two linguistic. I have already expended most of my philosophical powder on the first part, here is my response to the second. (My answer to the third will follow shortly.)
The second question raised by Maureen Koplow recently was this: “I wonder where the ight ending comes from.” I think Maureen is wondering about the ‘Silent GH’ in English words. Here are my thoughts on that subject.
To understand this one, we need to know a little about phonology, the scientific study of the sounds of language. Specifically, we need to know that the letters G and K represent sounds that are identical except that we vibrate our vocal cords pronouncing [g] (the way I represent sounds rather than letters–click to hear) but not when uttering [k] (click to hear).
There is a third member of the group found in Scots English (CH), Dutch (G), German (CH), and Russian (X) (click to hear). Let’s call this sound [kh]. It is identical to [k] except that the the back of the mouth is not fully closed in its pronunciation, allowing a bit of air to escape from the back of the throat, making a slight hissing sound. It sounds a bit like clearing your throat, so I always warned my students practicing this sound to put their hand in front of their mouths, especially anyone with a post-nasal drip.
OK. The sound represented by the silent GH in English was once a [k] in Proto-Indo-European (PIE—as mentally nutritious as it is delicious). That sound became [kh] over the course of the development of ancient Germanic languages like Old English. We still find this sound, as mentioned before, in Dutch, German, and Scots English. In most dialects of English, however, it reduced itself to [h], a sound so slight that has disappeared altogether from English everywhere except at the beginning of words. However, although the sound has disappeared, we continue spelling it.
You will find relatives of what once was GH represented as G, K or CH in other Indo-European languages. The word for “might” in German appears as mögen and möchten in German, mogu “I can” in Russian. The word for “night” in German is Nacht but in Latin nox, noctis (where C = [k]).
So words in English containing the Silent GH mark the spot where a real sound once stood. While English speakers are not at all resistent to changing their ways, we are very reluctant to change the way we spell our words, a trait that forces our children (and many adults) into years of misery trying to learn how to spell words they have no difficulty in uttering.