If you have any general concerns about your child, you should always speak with your child's class teacher in the first instance, as they will probably be able to give you the information that you need.  If you have some more specific questions relating to Special Educational Needs (SEN) which the teacher is unable to answer, then you will need to speak with the Special Educational Needs Co-ordinator (SENCo).  Class teachers and staff will also speak with the SENCo if they have any concerns about your child.