@RIL suggestion may be perfect and useful for you. You can also look at editing your script/captions in an external file and then reading in the file directly - that way any updates can be tracked as a line number.
Check out the add-on for reading a file into Isadora here: https://troikatronix.com/add-o...
Alternatively, the possibility of doing the same with the 'Data Array' actor is not overly complicated - see example patch attached:
Best Wishes
Russell