This template embeds text in a specific language according to its ISO language code, assisting the user agent (the web browser) in choosing the best way to display that text. This template otherwise does no special formatting whatsoever apart from that already specified by the Xenoblade Wiki's stylesheet and any custom stylesheet provided by a registered user for their own browsing.
The template's first argument is the language code.
The template's second argument is the text in that language.
...displays ダグ (Doug) in more appropriate text formatting for the Japanese language according to the language code "ja" for Japanese.
If the second argument contains an ASCII equals sign ("="), it should be prefixed with 2=, for example:
...displays ダグ=バレット. (Though this is a somewhat artificial example, as it would be more typical in this scenario to use a non-ASCII "full-width" equals sign, as in ダグ＝バレット.)