My research moves around the school from different perspectives but with the foundation of communication and the school's sound environment. Key aspects are speech comfort: the ability of the teacher to be heard through sufficient sound environment (acoustics and background / activity sounds) and with effective voice and communication (voice load, voice quality, nonverbal communication) and listening effort: the child's potential effort in perception of the spoken and language understanding in relation to the child's cognitive capacity. Our intervention research in schools concerns teacher training and the effects on the well-being of teachers and children and the linguistic capacity of the children.