I've noticed that some people here in Utah say "heighth" instead of "height." I think it may be an extension of the pattern set by width, breadth, and length, but I'm pretty sure that saying "heighth" is incorrect. I looked it up in the dictionary and way back in the day it used to be acceptable to use, but that was hundreds of years ago. For that matter, spelling it as hight used to be correct. But I don't think people who say heighth are referring to the Old English word when they add the voiceless dental fricative.
Speaking of voiceless dental fricatives, did you know that of the 60 languages with over 10 million speakers, only 5 languages use the "th" sound? Those languages are English, Arabic, Castilian Spanish (i.e. Spanish spoken in Spain), Burmese, and Greek. Some other lesser-known languages that use the voiceless dental fricative (isn't that so much fun to say?) are Fox, Shark Bay, Welayta, and Emiliano-Romagnolo.