Yes, TONGUE is a Scrabble word!

Letter values in Scrabble US: T 1, O 1, N 1, G 2, U 1, E 1.

Is it a valid word?

TONGUE is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a mobile mass of muscular tissue covered with mucous membrane and located in the oral cavity
a human written or spoken language used by a community; opposed to e.g. a computer language
any long thin projection that is transient
a manner of speaking
a narrow strip of land that juts out into the sea
the tongue of certain animals used as meat
the flap of material under the laces of a shoe or boot
metal striker that hangs inside a bell and makes a sound by hitting the side

Also: natural language.