Completely different words used for writing and speaking

A Japanese friend of mine asked me if this existed in English. For example, in Japanese, when referring to the company of your client, you say onsha (御社) when speaking, and use kisha (貴社) when writing.

Does the same kind of thing happen in English? I know it's very common to abbreviate words in speech but I can't think of a situation in which there would be a completely different word used for speaking.

I don't know if it's analogous because I don't speak Japanese, but how about the fact that when writing, we apply the honorific "Mrs." before a married woman's name to address her, which is actually an abbreviation of the word "mistress," but when speaking to her, we address her using the honorific "Missus"?

Another example might be dates. We rarely say dates aloud how we right them, not even when we're reading. If the date is written as "September 5, 2019" or "9/5/19," which are the two standard ways of writing dates in the US, I never speak that as "September five, two-thousand nineteen" or "nine slash five slash nineteen," instead, I invariably read it aloud as "September fifth, two thousand nineteen."

Even numbers themselves use written characters when they appear as numeral that do not jibe with any phonetic representation of what they convey. Now, we're so used to that, we see past it, but other languages at the very least use letters to represent their numbers, like Hebrew, the number one being the first letter of the Hebrew alphabet, the number two being the second letter, and so forth. In English, though, there's no association at all, the symbols for numbers (i.e., numerals) being completely arbitrary of independent of our spoken language.