The representation of the deaf-mute children as a collective trying to learn to communicate with others who cannot understand them quite clearly contrasts the concept of Mounir's that a single voice can speak for everyone.
This sentence juxtaposes Mounir's notion that a single voice can speak for all with the portrayal of deaf-mute children as a group seeking to connect with others who may struggle to comprehend them, emphasizing the complexities of communication and representation.