php, php3, php4
"abc", 'abc'
_("abc")
gettext, dgettext, dcgettext; starting with PHP 4.2.0
also ngettext, dngettext, dcngettext
textdomain function
bindtextdomain function
setlocale (LC_ALL, "")
xgettext
printf "%2\$d %1\$d"
An example is available in the examples directory: hello-php.