I'm assuming by "Nihongo Language" you mean how to say the Japanese language?
Nihongo itself means the Japanese language.
By adding the sufix "Go" which roughly means language to the word for Japan (Nihon) it reads as the Japanese Language.
This also works for most of the other Languages like French (Furansugo) or German (Doitsugo).
In Japanese, "Nihon"、(日本、にほん) means "Japan", and "go" (ご、語), means "language". So, Nihongo (にほんご、日本語) means "Japanese language".
Yours sound's so much better than mine. Thanks for being a great community helper jace75! <3 It's always a pleasure to find your answers!SebastianMichaelis
Commented 7 years ago