जिह्वा वै ग्रहः स रसेनातिग्राहेण गृ-हीतो जिह्वया हि रसान्विजानाति ॥ ४ ॥
In plain words
The tongue is a grasper — seized by taste itself, its own over-grasper. Because it is through the tongue that we know what things taste like.
Close to the Sanskrit
The tongue, indeed, is a grasper; it is seized by taste as the over-grasper; for by the tongue one discerns tastes.