How to Change JQuery Validator Language Message

The best method is to extend the plugin like this when needed

$.extend($.validator.messages, {
    required: "my required message",
    ....
});

If you look into the directory "localization", you could find different .js files that cointains error messages in different languages. [something like "messages_XX.js"]

Choose the file of the language you need and just add the following line, into the tag , after the inclusion of the jquery.validate.js

<script type="text/javascript" src="localization/messages_XX.js"></script>

Do it like this:

$(document).ready(function() {
  $("form#login").validate({
    lang: 'en'  // or whatever language option you have.
  });
});

If the language you wish to supply is not one of the default languages, then do this:

$.tools.validator.localize("fi", {
    '*'          : 'Virheellinen arvo',
    ':email'     : 'Virheellinen sähköpostiosoite',
    ':number'    : 'Arvon on oltava numeerinen',
    ':url'       : 'Virheellinen URL',
    '[max]'      : 'Arvon on oltava pienempi, kuin $1',
    '[min]'      : 'Arvon on oltava suurempi, kuin $1',
    '[required]' : 'Kentän arvo on annettava'
});

  $("form#login").validate({
    lang: 'fi'
  });

See these instructions for more.