Here's a fun snippet I ran into today:
/\ba/.test("a") --> true
/\bà/.test("à") --> false
However,
/à/.test("à") --> true
Firstly, wtf?
Secondly, if I want to match an accented character at the start of a word, how can I do that? (I'd really like to avoid using over-the-top selectors like /(?:^|\s|'|\(\) ....)
Stack Overflow had also an issue with non ASCII characters in regex, you can find it here. They are not coping with word boundaries, but maybe gives you anyway useful hints.
There is another page, but he wants to match strings and not words.
I don't know, and did not find now, an anchor for your problem, but when I see what monster regexes in my first link are used, your group, that you want to avoid, is not over the top and to my opinion your solution.