Woot! I made a stupid mistake. The bug is fixed now and multi line support is working!
http://helicoid.de/scumm/mkspeech.zip
...I probably need to introduce versioning soon....
It works amazingly good...
of course still some things to polish and iron out.. but that should definitely be the way to go.
EDIT: There are some patterns that are not matched yet, like things in quotes. There should be no need to add that to the mapping.txt, as this can be easily added in the lookup function.