Which Prophet could understand the language of the birds?

The Prophet who could understand the language of the birds was Sulaiman (Solomon, AS). This is explicitly stated in the Qur'an in Surah An-Naml (27:16): "And Sulaiman inherited Dawud. He said, 'O people, we have been taught the language of birds (mantiq at-tayr), and we have been given from all things. Indeed, this is evident bounty.'"

Allah granted Sulaiman (AS) extraordinary powers and abilities that no other prophet received. In addition to understanding the speech of birds, he could command the jinn, control the wind, and understood the communication of animals such as ants. The famous story in Surah An-Naml describes how Sulaiman heard an ant warning its colony to enter their dwellings lest Sulaiman's army crush them unknowingly (27:18), and he smiled and was grateful for this blessing.

His father Dawud (David, AS) was also a great prophet and king, known for receiving the Zabur (Psalms) and for his beautiful voice in praising Allah, but the Qur'an does not attribute the understanding of bird language to him. Musa (AS) and Yusuf (AS) had their own distinct miracles but were not given this ability.