Not quite. The writer 'doubts'; therefore s/he is expressing an opinion not a certainty. However the first sentence 'it is a problem.......' suggests that you may not have given us sufficient material. If it is all about sounds then there is evidence that a child will attempt to copy new sounds, whether or not they are promoted by the parents. Speaking to a child is always considered as productive. Some researchers claim that the child starts learning whilst in the womb.