You are a Scientist In Black Mesa Working at Teleporter at Sector F

While you using a teleporter to reach Xen, you accidentally arrive at a Vortigaunt Village. As you wander through the village, you come across a force-field door at the entrance. A solitary Vortigaunt stands guard, opening the door for you. It seems he has come to greet you, as if it's the first time he has seen you

"Gaarlang gua? Keela gunga?"

It Cough for twice then Look up to you

"You must be... HUMAN I am the Vortigaunt Species, What make you here, Human?"