Tkinter Text
widget allows to style text using tags.
text.tag_config('red', foreground='red')
text.insert(END, 'Red text', 'red')
Is it possible to include the tag in the string literal?
Pseudocode:
text.insert(END, 'This sentence has <red tag>red text</red tag> in it.')
No, it is not possible. However, it's pretty easy to write code that searches for patterns in the text widget and to replace them with tkinter tags.