Complex sentence: Unlike the larynx of mammals, the syrinx is located where the trachea forks into the lungs, and because of this some songbirds can produce more than one sound at a time.
Split into simpler sentences: Unlike the larynx of mammals, the syrinx is located where the trachea forks into the lungs. Thus, lateralization of bird song is possible and some songbirds can produce more than one sound at a time.