Go to general plugin’s options – /wp-admin/options-general.php?page=qtranslate-x#general and in section “URL Modification Mode” choose “Pre-Path Mode” and then also check “Hide URL language information for default language” – like this:
Go to general plugin’s options – /wp-admin/options-general.php?page=qtranslate-x#general and in section “URL Modification Mode” choose “Pre-Path Mode” and then also check “Hide URL language information for default language” – like this: