Q From Les Dixon: When I moved to Canada from the UK 25 years ago I noticed that some people, not many, used the word heighth rather than height. I don’t think I’d ever heard this in England and at first I thought it was just a slip of the tongue, but I now hear it more often, even by a television reporter on one occasion. The words width and length are correct, what about the word heighth? Was it ever used in the past?
A It was. In fact, until the end of the seventeenth century, highth or heighth were its standard spellings. The word was formed in Old English from high, plus -th, the exact analogue of width, breadth, and length. If word history were the only consideration, we all ought still to be using highth.
The reason why we don’t comes down to dialect pronunciation in parts of Northern England in Middle English times, in which the -th ending was pronounced as /t/. In Southern England, it was said instead like the initial th in thumb. During the seventeenth century, the Northern form triumphed over the Southern, and the spelling followed suit. (Width and length didn’t follow because final dt is not a common consonant cluster in English and is hard to say.)
However, heighth continued to be widely heard. Charles Dickens used it frequently — as here in Great Expectations: “Pip, I wish you ever well and ever prospering to a greater and a greater heighth”. It still exists in several English dialects down to the present day. It has also survived in parts of North America, which have tended to cling to older pronunciations.
Because of its odd history, we can hardly argue that highth is truly an error, more an archaism. Though nearly everyone now spells it height, it’s not that uncommon to hear it said as /haɪtθ/ among educated people in North America, and some authorities there consider it to be a permissible variant.
So strong is the ending that it is not unknown to hear people use coolth, a word which some dictionaries mark as archaic, but which has had a resurgence in favour in recent decades.