sedの勉強がてらmultilingual SLAXのisolinux.cfgの主要部分だけ抜き出すスクリプトを書いてみた。'mlangs.sed'とでもして実行属性つけて
$ ./mlangs.sed isolinux.cfg | sort
してみて。

#!/bin/sed -nf
#
/^label/!d # skip unless /^label/
/^label/{ # /^label/ section
# read /^label/ ... /^append/ lines
:loop
N # read next line
s/label ..\n// # erase abbreviated label
s/label .. .*\n// # erase abbreviated label with some modification
s/kernel.*\n// # erase /^kernel/ line
/append/! b loop # read until /^append/ line
# read 'append' line
N # read /^append/ line
s/append.*lang/lang/ # erase 'append' .. 'lang' in /^append/ line
# post process
s/label // # erase 'label '
s/\n/: / # convert 1st newline to ': '
s/\n$// # erase last newline
}
#
/^slax/d # erase /^slax/ line
/^linux/d # erase /^linux/ line
/^$/!p # show unless null line
d # clear pattern space for next cycle
#
# end of mlangs.sed