If you use voice dictation to type on your iPhone, you might have noticed that Siri/dictation uses the "common" spelling of proper nouns. If you use a less common spelling often, you might also be irritated by the constant misspelling. This post (and the included video) show you how to setup a contact to "teach" Siri/dictation how you want to spell that proper noun. In my examples, I make a new contact, but you could also adjust the existing contact to add the "Phonetic" field if your proper noun is a person already in your contacts.
Here is a breakdown of the steps in the video:
Add a contact in your iPhone Contacts app with the first name of the word how you want it spelled. If it's a word that should always be capitalized, make sure it is capitalized here. If it shouldn't, make sure the name is written in lowercase.
After typing in the first name, scroll to the bottom & tap "add field" then tap "Phonetic First Name". Scroll back up and you'll have a new field under the name of phonetic first name.
Tap that phonetic first name field and dictate in the word. This will tell the voice capture how the name "sounds" then tap done to save it. (It could be typed, but dictation ensures you get the spelling matched precisely.)
Double-tap the home button to bring up the app switching screen. Swipe up over the Contacts app to force close it. Also, swipe up over whatever app you want to use voice dictation with immediately, to close that too. This forces the apps to reload the settings for dictation ASAP so your fix is ready for use.