Sanjaya uvaacha:
evamuktvaa hrisheekesham gudakeshaha parantapa |
na yotsya iti govindamuktvaa tushneem babhoova ha || 9 ||

Sanjaya said:

Having spoken this to Hrisheekesha, Gudaakesha, the scorcher of foes, said to Govinda : “I will not fight”, and became silent.

evam : this
uktvaa : having spoken
hrisheekesham : Hrisheekesha (Shri Krishna)
gudaakesha : Gudaakesha (Arjuna)
parantapa : scorcher of foes
na yotsya : I will not fight
iti : this
govindam : to Govinda (Shri Krishna)
uktvaa : said
tushneem : silent
babhoova  ha: and became

In the last verse, Arjuna had surrendered his decision-making to Shri Krishna, and had asked him for guidance. Arjuna knew that he was in no shape to make that decision himself, let alone fight. So he eventually proclaimed that he would not fight, and became silent.

We should note that it was not just Arjuna’s voice that became silent. His mind, though not totally silent, became calmer than what it was in the last verse. Otherwise, it could not have assimilated the teaching that was about to follow.

Also note that the narration has shifted back to Sanjaya in this verse, and the meter has changed back to normal. He refers to Arjuna as Gudaakesha or “conqueror of sleep”, and Shri Krishna as Hrisheekesha or “conqueror of the senses”.