Recently I've noticed that many people are pronouncing the word 'height' as
That's right, heigth.
I've only ever heard this pronunciation mistake in the last few years. Maybe it's just an issue in Texas? Has anyone else noticed this?
Heighth is no error
It is a misunderstanding that the spelling or pronunciation of heighth is an illiterate and uneducated error. Although many wrongly consider it such, history is not on their side, nor are the better dictionaries.
Despite how in particular over the last century the heighth spelling has come to be stigmatized, heighth is a perfectly legitimate word of ancient lineage. It was used not only by Shakespeare and Milton, but even by Charles Dickens, who wrote considerably later than the first two.
The spelling that is no longer used is hight, although it was once common. Interestingly, Shakespeare variously employed not only height and heighth but also hight, depending on the work:
Editions of Anthony & Cleopatra with normalized spellings now generally read:
The thing to understand, though, is that this is not some spelling that died out when the reign of Elizabeth I came to an end. It remained in use by writers of unimpeachable integrity up through the 19th century and sometimes even into the early 20th.
All three forms of the word — height, heighth, hight — were long used, but in truth, only the last of those has completely fallen away. For while the OED no longer admits hight as a modern spelling, it does present both height and heighth as admissible variants, with -th listed second. In its rather long etymology section on this word, it observes (bold emphasis mine):
So if you don’t mind being falsely accused of being wrong, or perhaps with somewhat stronger evidence of writing in an affected manner, go ahead and use it. After all, Microsoft doesn’t know everything about English, so you should never trust its software in matters of writing. :)
Here sorted by date are the OED citations for the heighth spelling, excepting only those already given:
What the Dickens!
But that’s not all. Consider the Charles Dickens story “Doctor Marigold’s Prescriptions”, published in 1865:
As you see, that sounds perfectly fine. Please note that modern editions of that work are not respelled as so often now occurs with Shakespeare. Heighth is retained just as Dickens wrote it.
Notice also how in the Dickens citation, heighth has a distinct advantage when used in conjunction with breadth or length, since now one retains a certain parallelism of form that would be lost were it spelled height.
That said, I personally would not in general recommend writing heighth unless you are writing a period piece. I say this not out of correctness, but to fend off the hypercorrective efforts of those with less education, given how few today realize its actual provenance and legitimacy.
If you do choose to use heighth, however, you should probably be prepared to back up your use at the very least with the OED, which attaches no stigma to that spelling, and probably with citations from other writers of note.
Well, it seems that the misconception regarding the spelling/pronunciation is due to some confusion regarding dimension-related words:
On his World Wide Words website, etymologist Michael Quinion describes the phenomenon and its origins here:
He sums up its current status thus:
 Pronunciation help is provided here:
A couple of points: why do you assume it to be a mispronunciation? It used to be common in my youth in New Zealand, where we speak British English. It started to fall out of use around the end of World War Two, when American English became popular, due mainly to Hollywood influences. It goes back at least as far as 1588.
I feel it is a "dialectical variant" and there are sufficient proofs that it is simply a popular mispronunciation the educated population have grown too tired of correcting. Just because a mispronunciation has become commonly used doesn't make it a legitimate word.
"Heighth" is a chiefly dialectal variant of "height".