[quote=Lennon79]
Sorry mate, I don't mean to be argumentative but that simply isn't the case. Nii-chan and Nee-chan are simplifications of Onii-chan/Onee-chan, both referring to an elder brother and sister respectively. There is no suffix for a younger sibling in Japanese; the nearest would be the words otouto and imouto, i.e. little brother and little sister, however neither of these are used in the same way as Onii/Onee-chan. An older sibling would simply use their little sister/brother's name, perhaps with -chan or -kun as a suffix.
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