Phoebe,
the language packs are only for the backend.
What I have recommended in the past is install the Custom System Messages add-on which lets you define which template will be used for your error pages, instead of the Speciality Templates that are only editable within the Control Panel.
Now you can do you own language switching in the templates of your choosing for the errors using global variables or whatever method you are using.
Please expand on this. Clearly there are messages that are printed out to the front end within the language packs. (i.e. Invalid password, Field is required, etc….)
I have the Custom Sys Messages extension installed. However like the OP asks, within the custom templates, how would I go about switching the language pack to let say “Japanese” to display error messages back to the user upon login or form sumbissions. Here is what Im trying to convey.
Custom User Message Template:
Somehow we need to use a conditional to use a different language pack.
{if {country_code} =="jp"}
{lang_pack = "japanese"}
{if:else}
{lang_pack = "english"}
{/if}
{embed="inc/top" loc="home" page_title="Error"}
{meta_refresh}
<div class="content">
<h1>{heading}</h1>
{content}
{link}
{action}
</div>
{embed="inc/bottom" loc="home"}
Even if we have to surround each variable (heading, content, link) that would be fine, just point us in the right direction or at least tell us it is not possible so we can let our clients know.
Thanks