Use Options → Install Add-ons to install the add-on called "Translate XMLmind XML Editor" then restart XMLmind XML Editor (XXE for short).

After installing the add-on, the translatexxe command-line utility is found in the translate_xxe/ subdirectory of one of the two addon/ directories scanned by XXE during its startup.

Use translatexxe.bat on Windows and the translatexxe shell script on Linux and on the Mac.

Create a new translation from scratch:

C:\Prog…\translate_xxe> translatexxe -l fr -e windows-1252 \
    -m fr.txt

Or update an existing translation. The existing translation is either found in a message Jar (example: fr_translation.jar) or in an add-on Zip (example: fr_translation.zip, itself containing fr_translation/fr_translation.jar and fr_translation/fr_translation.xxe_addon):

C:\Prog…\translate_xxe> translatexxe -l fr -e windows-1252 \
    -m fr.txt \misc\fr_translation.jar

or:

C:\Prog…\translate_xxe> translatexxe -l fr -e windows-1252 \
    -m fr.txt \misc\fr_translation.zip

All the above commands generate a text file. If you intend to use a specialized translation editor^[5] rather than a text editor, you may want to generate an XLIFF file. In such case, specify a message file having a "xlf", "xliff" or "xml" extension. Example:

C:\Prog…\translate_xxe> translatexxe -l fr \
    -m fr.xlf \misc\fr_translation.jar

Message file fr.txt looks like this:

++++++++++com/xmlmind/guiutil/Messages.properties
#################################################

### ChooseFile ---

openFile=Open File
openFile=

CF.overwriteFile=Overwrite existing file\n\
"{0}"?
CF.overwriteFile=

----------com/xmlmind/guiutil/Messages.properties
++++++++++com/xmlmind/xml/dtd/Messages.properties

invalidDefaultValue=default value "{0}" of attribute "{1}" of "{2}" is invalid: {3}
invalidDefaultValue=

----------com/xmlmind/xml/dtd/Messages.properties

Translate all the messages found the “recommended sections” (underlined section title). See Section 3, “How to correctly translate a message”.

++++++++++com/xmlmind/guiutil/Messages.properties
#################################################

### ChooseFile ---

openFile=Open File
openFile=Ouvrir Fichier

CF.overwriteFile=Overwrite existing file\n\
"{0}"?
CF.overwriteFile=Écraser le fichier existant\n\
"{0}"?

----------com/xmlmind/guiutil/Messages.properties
++++++++++com/xmlmind/xml/dtd/Messages.properties

invalidDefaultValue=default value "{0}" of attribute "{1}" of "{2}" is invalid: {3}
invalidDefaultValue=

----------com/xmlmind/xml/dtd/Messages.properties

In a text file, in addition to normal characters, it is possible to use the following escape sequences: '\n' (newline), '\t' (tab), '\uXXXX' (where XXXX is the code of a Unicode character in 4-digit hexadecimal notation). '\uXXXX' is especially useful because it's the only way to specify characters not supported by the encoding passed to the -e command-line option. Example: '\u2192' (right arrow).

Test your translation by first converting the text file to a message Jar:

C:\Prog…\translate_xxe> translatexxe -l fr -e windows-1252 \
    -j ..\addon\fr_translation.jar fr.txt

Make sure that the message Jar is found inside one of the two addon/ directories scanned by XXE during its startup. Then start XXE, clear or disable its Quick Start cache^[6] and restart XXE.

If, after restarting XXE, you don't see its user interface translated to the target language, then this means that the locale of your computer (example: en-US) does not correspond to the target language (example: fr). When this is the case, use Options → Preferences, General section, to change the locale used by XXE from "(default)" to the locale corresponding to the target language (example: "français").

Finally convert the text file to a ready-to-deploy add-on Zip:

C:\Prog…\translate_xxe> translatexxe -l fr -e windows-1252 \
    -p \misc\fr_translation.zip fr.txt

You may want to specify for the name of the author of the add-on using the -a command-line option. A string starting with "mailto:" (example: "mailto:jane@doe.name") gets a special treatment. A string starting with "<html>" and followed by well-formed, properly escaped, XHTML (example: "<html><a href='http://www.doe.name/'>Jane Doe &amp; al.</a>") also gets a special treatment. Otherwise, the string is understood to be plain text (example: "Jane Doe & al.").

C:\Prog…\translate_xxe> translatexxe -l fr -e windows-1252 \
    -a "mailto:jane@doe.name" -p \misc\fr_translation.zip fr.txt