Hi Burakus1224
welcome to the Apple (user-to-usr) Community!
Re: iPhone 13 iOS 18.2.1 Siri and dictation won't turn off.
....“your request is being processed, Siri and dictation will be deleted.” He says and doesn't delete it.
You might want to try checking other settings:
If you haven't already: Try tapping on Settings > ScreenTime > Content and Privacy restrictions > Intelligence and Siri > Then tap on Siri and Dictation > if on, tap to turn off
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Re: I've been trying for 12 hours to delete it, but it won't delete.
Else: Wondering if updating your iOS version may help. Keeping iOS software up-to-date can often help avoid issues. Apple Support's article : About iOS 18 Updates - Apple Support says iOS 18.5 is the latest, and ...
"This update introduces ... features, bug fixes, and security updates for your iPhone"
If you decide to update your iOS version, it is always wise to back-up your iPhone first.
Then you might want to update from Settings > General > Software updates.
All the best :-)