[lucagalbu]

Hi all!!
Can someone please explain me this phrase:

nanika taberu mono ga aru

My problem is thah I don't understand why I have to use nanika and mono: mono means "thing" but nanika means "something", so by using nanika and mono together, don't I repeat twice the word "thing"? Shouldn't I say:
ikutsuka taberu mono ga aru or taberu nanika ga aru

End another question please:
in order to translate "I speak japanese" I say:
a) nihongo wo hanasu
b) nihongo de hanasu

Thanks very much