Editing Module:Lang/doc (section)

===Parameters===
* '''key''' - Key string to localize
* '''lang_code_override''' (OPTIONAL) - Overrides the current language to a specific language code
* '''fallback_str''' (OPTIONAL) - Passing <code>en</code> causes it to return the english localization if it can't be localized to the current language. Passing any other string causes it to return that string if it can't be localized. Both have [[Template:MissingValveTranslationTooltip]] appended. Use this very often as some keys are not yet localized in every language by the game. Passing <code>dictionary</code> causes it to return the translation via [[Data:Dictionary]] if it can't be localized. If parsing the fallback_str from lua and is computationally expensive (i.e. add_space_before_cap), consider using fallback outside this function so it only computes when needed.
* '''remove_var_index''' (OPTIONAL) - Removes %variables% from the resulting string. -1 also removes the character prefixing %variables%, while 1 removes the postfixed character, and 0 removes only the %variables%.

NOTE: Optional parameters are ideally named when not all parameters are provided, though named parameters can only be passed by invoke, and not internal lua calls.