In PHP 5.3, mb_language() returns "neutral" by default for me.
(PHP 4 >= 4.0.6, PHP 5)
mb_language — Set/Get current language
$language= mb_language() ] )
Set/Get the current language.
Used for encoding e-mail messages. Valid languages are "Japanese", "ja","English","en" and "uni" (UTF-8). mb_send_mail() uses this setting to encode e-mail.
Language and its setting is ISO-2022-JP/Base64 for Japanese, UTF-8/Base64 for uni, ISO-8859-1/quoted printable for English.
language is set and
language is valid, it returns
TRUE. Otherwise, it returns
language is omitted, it returns the language
name as a string. If no language is set previously, it then returns