In plain words
Then Hrishikesha, as if smiling, spoke these words to the grieving Arjuna between the two armies, O Bharata.
Word for word
To him, O Bhārata, Hṛṣīkeśa, as if laughing, spoke this speech, [to him] despairing in the middle of both armies.
तमुवाच हृषीकेशः प्रहसन्निव भारतसेनयोरुभयोर्मध्ये विषीदन्तमिदं वचः