I think you can do it easily with a List of pairs of hours in numbers + words, and a List of pairs of minutes in numbers + words. (including quarter, half etc). Your example should include am or pm in the text version.
So, you can write a procedure that reads the current time, looks-up it's elements in the Lists and builds the textural time with those List Items.
The snag is, you can't build the App as an always-running-clock because that requires Android Background Services and App Inventor does not support them. There are other easy-to-use languages that do, if that (a clock) is what you need.
Here is my effort on this, not pretty but seems to work OK.
Handles every minute
Uses a quarter to, a quarter past, and half past
Uses textToSpeech to speak the time