$chr(22) is your key bud...
on *:TEXT:*:#:{
if ($chr(22) isin $1-) { echo -a Highlighted word has been detected in $+($nick,s) phrase. }
}
you can do a simple gettok to get the word but this is just to show quick and simply how you capture a highlight.
BTW here is a method sure proibably can look better but what i did for u is create a small script you can execute by typing /rodr
this will open a @rodra window and list the chars from 1 to 200 what they are, notice youll see a A appear beside some chars well thats me because it shows you what some chars do for in your example CHR 22 creates a highlight so by doing a IF statement on TEXT i can capture CHR 22