A new study from researchers at the University of California, Berkeley, has found that our brains can perceive speech as song after repeated listening. The study, published in the journal "Current Biology," could help explain why we sometimes hear songs as lyrics, or why we can sing along to songs we've never heard before.

The researchers conducted a series of experiments in which participants listened to sentences spoken by a computer-generated voice. The sentences were repeated multiple times, and the participants were asked to identify whether each sentence was speech or song.

The results showed that the participants were more likely to identify the sentences as song after they had been repeated multiple times. This effect was strongest for sentences that were spoken in a sing-song voice, but it also occurred for sentences that were spoken in a normal speaking voice.

The researchers believe that the brain's ability to perceive speech as song is due to the way that the brain processes sound. When we listen to speech, our brains use a variety of cues to identify the sounds that we are hearing. These cues include the pitch, rhythm, and timbre of the sounds. When we listen to song, our brains use many of the same cues to identify the sounds, but they also pay more attention to the melody of the song.

The researchers believe that the repeated listening to sentences in the study caused the participants' brains to pay more attention to the melody of the sentences. This, in turn, caused the participants to perceive the sentences as song.

The study's findings could have implications for understanding how we learn language and music. The findings also suggest that our brains may be able to process sound in more ways than we previously thought.