Six-month old infants who obviously cannot speak, can discriminate between the sounds of different consonants. However, if they are sucking a pacifier the distinction is much harder because the pacifier interferes with tongue movements that help the infant attempt to repeat the sound of the consonants it just heard. Remove the pacifier and the infant again discriminates the different sounds. The auditory distinction of consonants that do not require tongue movements is not hampered by the use of a pacifier. It is likely that any instrument that in young age interferes with tongue and mouth movements will negatively affect not only sound discrimination but also speaking.