There are various snake-morphs living in the desert:
Nagas - those with full snake conversion, tongues that make standard speech difficult, scales torsos and arms. Long snake tongues, powerful sense of taste and smell.
Lamias - Snake from the waist down, often excluding genitalia which is more human, breasts, upper body typically has little or no scale or snake morph. Possibly long prehensile tongue.
They live in different hiding places, frequently living among one another peacefully. Outsiders are not unwelcome, but often have trouble communicating with the more morphed individuals like the Naga.