Hello,
What exactly do you mean by "translate the numbers in date/time fields"?
If you want to convert numeric month to English, like "12" into "Dec", then it depends on when you want this to happen.
If you want these English months appear in your CSV file, then I suggest that you look into the table-dumping script that you mentioned, and if that is not possible for some reason, then you could try doing this conversion with PHP after the CSV file has been created (this might be troublesome somewhat), but if you want this only in Excel, then I thought you could simply set the property of the column to "Date" format within Excel and configure as you want (or whatever Excel has for displaying data in Date format).
HTH.