Have CiviCRM follow CMS language with Joomla
To my knowledge, CiviCRM doesn't support automatic inheritance of the language in Joomla, yet.
But your idea to add lcMessages in the url was good. I was able to make it work using lcMessages=en_CA. It seems that you have set up your site in en_CA locale, not the default en_US.
The full url should be : https://www.voile.qc.ca/en/?option=com_civicrm&amp;task=civicrm/profile&amp;Itemid=609&amp;force=1&amp;gid=14&amp;lcMessages=en_CA