Syntax

Syntactic actants

Actant 1: whose tongue it is
(a) Genitive
(b) Possessive
Язык больного был белый. The patient's tongue was white.
Ну-ка, мальчик, покажи мне свой язык! Come on, little boy, show me your tongue!
NB When the word язык functions as a subject and does not have a descriptive modifier, the construction язык у + Genitive is often preferred to (a) and (b), above:
Язык у больного был белый. The patient's tongue was white.