user/javadoc/com/google/gwt/examples/i18n/MyAppWithLocales.gwt.xml

<module>
  <inherits name="com.google.gwt.user.User"/>
  <inherits name="com.google.gwt.i18n.I18N"/>
  
  <!-- French language, independent of country -->
  <extend-property name="locale" values="fr"/>

  <!-- French in France -->
  <extend-property name="locale" values="fr_FR"/>

  <!-- French in Canada -->
  <extend-property name="locale" values="fr_CA"/>
  
  <!-- English language, independent of country -->
  <extend-property name="locale" values="en"/>
</module>