“Width” has a TH at the end, so why doesn’t “height”? In fact it used to, but the standard pronunciation today ends in a plain “T” sound. People who use the obsolete form misspell it as well, so pronunciation is no guide. By the way, this is one of those pesky exceptions to the rule, “I before E except after C,” but the vowels are seldom switched, perhaps because we see it printed on so many forms along with “age” and “weight.”
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