Is Primal Whisperer legal in Standard, Modern, and Commander?

Primal Whisperer is legal in: Legacy, Vintage, Commander.

What type of card is Primal Whisperer?

Primal Whisperer is a Creature — Elf Soldier. Its oracle text reads: "This creature gets +2/+2 for each face-down creature on the battlefield. Morph {3}{G} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)"