The best experience is with text where you tell the user what's happening.
Google does their strength indicator with text:
Another example I've seen is with suggested or required criteria to force the user to generate a more secure password:
If you are debating about whether or not it's a good idea to use text or not, here's a great article:
Part of it depends on how tech savvy your users are and if they are able to recognize what the colour bar means. Without knowing who your audience is, all of our answers will be a shot in the dark but Google has a pretty widespread reach, so I feel that's a more appropriate example.
EDIT: I'm sure that Google has all the translations you need for this if you just use the language setting on the password page.