Just put the 'text detector' sprite into your backpack. To change which word it is looking for, just change up 'set targetWord to' You can also switch out 'when the green flag is clicked' for any other trigger. Switch out 'broadcast message 1' for any other result. Just dig around and work out how everything works, especially how sprite 3 detects the word.
Inspiration by @ItIsDagger All the code by me Please, do bug test. The word is 'and' It's all designed to take up the least space. Also, a word with "'s" is also detected. You can remove that too.