Hi Toshiro,
I'm not sure whether or not I have totally understood your question, but if I have, you are looking for force a language. If that is correct, then I think you need to do this on the way in rather than in the template (which is on the way out). That way when the request is processed, the language you want to use is already there.
If this is correct that you can try to do the following --
1. Create a Servlet Filter hook or a Service Pre Action hook.
2. In the hook add something similiar to the following --
request.getSession().setAttribute(Globals.LOCALE_KEY, Locale.<your-country>);
LanguageUtil.updateCookie(httprequest, httpresponse, Locale.CANADA);
ThemeDisplay themeDisplay = (ThemeDisplay) request.getAttribute(WebKeys.THEME_DISPLAY);
if ( Validator.isNotNull(themeDisplay) )
themeDisplay.setLanguageId( Locale.<your-country>.toString() );
if ( Validator.isNotNull(PortalUtil.getUser(request)) )
PortalUtil.getUser(httprequest).setLanguageId(Locale.<your-country>.toString());
</your-country></your-country></your-country>
That will set the values on the way in for the request, overriding what is there in the first place. Alternatively, if you know your user has their locale set correctly in their browser, then you can use this property --
#
# Set this to true if unauthenticated users get their preferred language
# from the Accept-Language header. Set this to false if unauthenticated
# users get their preferred language from their company.
#
locale.default.request=false
... Setting it to true will tell Liferay to use whatever the user is passing in as the Accep-Language value for the Http Request header as the language value.
