I've just had a chance to play with localization. What I've noticed is that we cannot change a field 'Title' as a change will not be displayed on the board. However, the strings search engine takes into account only that field, ommiting 'Phrase' one.
The problem appears when users will report wrong or inaccurate translation. We are now unable to find the string without switching first to English version, trying to guess English title and then getting back to ACP.
My suggestion: incorporate Phrase field into string search.
Nevermind. It's the built-in function I haven't noticed before. Sorry.