The goal of this clinical trial is to find out the role of background factors and gaze use in children's speechreading performance. The main questions it aims to answer are: * Which background factors and eye gaze patterns are associated with the best speechreading results in hearing children and those with hearing impairment/loss? * Are children's gaze patterns and facial expression discrimination associated with interpretation of emotional contents of verbal messages in speechreading? * What is the efficacy of intervention that is based on the use of a speechreading application to be developed? Participants will be * tested with linguistic and cognitive tests and tasks * tested with a speechreading test and tasks with or without simultaneous eye-tracking * about half of the participants with hearing impairment/loss will train speechreading with an application Researchers will compare the different age groups and the results of hearing children to those of children with impaired hearing to see if there are differences.