Dictation is a built-in feature on iPhones, and it shouldn't be missing on iOS 17.
If it is the iOS that is the culprit then all devices on iPhone 15 or iPhone 14 will not have the Dication. It's not always the update's fault! Many things can cause phone problems. If you tell people you think it's an iOS update, it might make it harder to fix the real issue. Remember, the right question often leads to the solution!
You need to specify the devices where you are facing the issue.
Did you c heck --> Go to Settings > General > Keyboard. Make sure "Enable Dictation" is turned on
Note: All languages do not have the Dictation feature. You have not specified the language (Keyboard) that you are using.
iPhone 15
iPhone 15 Plus
Dictation languages: English (Australia, Canada, India, Ireland, Malaysia, New Zealand, Philippines, Saudi Arabia, Singapore, South Africa, United Arab Emirates, UK, US), Cantonese (China mainland, Hong Kong), Mandarin Chinese (China mainland, Taiwan), French (Belgium, Canada, France, Luxembourg, Switzerland), German (Austria, Germany, Switzerland), Italian (Italy, Switzerland), Japanese, Korean, Spanish (Chile, Colombia, Mexico, Spain, US), Portuguese (Brazil, Portugal), Arabic (Kuwait, Qatar, Saudi Arabia, United Arab Emirates), Catalan, Croatian, Czech, Danish, Dutch (Belgium, Netherlands), Finnish, Greek, Hebrew, Hindi, Hungarian, Indonesian, Malay, Norwegian (Bokmål), Polish, Romanian, Russian, Shanghainese (China mainland), Slovak, Swedish, Thai, Turkish, Ukrainian, Vietnamese