It would be useful to have a tool available that flags possible translation file issues, such as:
- missing translations for (new) English messages
- mismatched parameters between English and non-English messages
- translation of keywords
- quoting problems (i.e. use of double quotes when single quotes should be used, use of single quotes when double quotes should be used. This is based on what's described in the MessageFormat api doc)
- mismatched characters such as < (when meaning smaller than), > (when meaning larger than), % etc.
- identification of invalid characters, specifically characters in the range of 0x00-0x1f (which are ASCII) and 0x7f-0xff
Note that such a tool cannot be definite (except about the missing messages) because the English messages are not following very strict formatting, and because what's acceptable syntax/grammar in one language may not work in another.
A discussion about a first cut at such a tool can be found at: