Apple offers several tools in the Accessibility / Read & Speak settings of iOS and iPadOS which are designed for low vision users who can still see the screen but who find it difficult or tiring to read text. VoiceOver users are recommended to avoid the Read & Speak tools and to use VoiceOver gestures to have text spoken. In my opinion low vision users should consider turning on VoiceOver when they need text to be spoken rather than use the Read & Speak speech tools so long as they don't have a problem performing simple VoiceOver gestures or remembering them. The Accessibility Reader's ability to change how text is displayed could be helpful if you prefer to use your vision but if you want text spoken it's very easy to dip in and out of VoiceOver by asking Siri to turn it on or off and then using a few simple VoiceOver gestures in conjunction with your vision to have text spoken. Also, if your sight gets a little worse then you will have some useful experience of VoiceOver on which to build. Apple's Read & Speak tools offer an alternative to dipping in and out of VoiceOver to have text spoken that some people may prefer and for those who prefer to use their vision the Accessibility Reader can make sections of text in any app readable in font sizes and colours of your choice.
iOS 26 introduced the Accessibility Reader which lets you view or listen to text content from any app in a customisable full-screen view. As well as its speech feature Accessibility Reader reformats the text in a font and colours of your choice and simplifies the layout to improve readability.
To make Accessibility Reader available go to Settings / Accessibility / Read & Speak and turn on Accessibility Reader. There is also an option here to enable AutoPlay in Accessibility Reader which, if turned on, will automatically begin to speak the text when Accessibility Reader is started. Once Accessibility Reader is turned on in Settings it can be started using the Accessibility Shortcut, a triple click on the side button or home button if one is present on your iPhone or iPad. Other ways to start Accessibility Reader include using the Control Centre or Setting Accessibility Reader as a Back Tap action at Settings / Accessibility / Touch / Back Tap. The Accessibility Reader behaves like an app so when you have finished with it swipe a finger up from the bottom of the screen to the centre which will start the app switcher and then tap the app to which you want to return.
For all the details check out the Apple Support description of Accessibility Reader.
Before I direct you to Apple's description of these tools I have a few comments about the Speak Selection tool.
First, you may not know how to select text.
Here's how to select text when VoiceOver isn't being used.
If you are typing text and want to select some of the text you have typed, double tap with one finger to select a word, triple tap with one finger to select a paragraph or tap a word and rest your finger for a while and then lift your finger. Blue blobs willappear on markers to show the beginning and end of the selection. The selection can be adjusted by dragging the blue blobs. This can be a bit fiddly with low vision.
And just one word of caution. If you are entering text your selection will be deleted if you unintentionally tap a key on the keyboard.
If you aren't entering text but reading text such as an email in your inbox you may find that only the tap and rest gesture is available.
For the details read Apple Support's description of speak selection and speak screen