Most students begin kindergarten knowing some letters of the alphabet and a few sounds. They achieve reading milestones when they are able to recognize all letters and produce the sounds for each one. They will be able to decode -- sound out -- simple three-letter words by saying the sound for each letter, then blending them. Your child should be able to read simple books using a combination of phonics and context clues by looking at the pictures. He will also be able to listen to a story that is read aloud, then answer questions about it.
Math milestones for kindergarten will indicate a child's ability to recognize numbers when presented randomly and to count beyond 10. If your child is able to determine "more than" and "less than" by looking at objects or pictures, this indicates adequately developed number sense. Your child should also know the names of basic shapes and sort objects by size, shape and color.
A kindergarten student's language skills will be remarkably different by the end of the year. Evidence of progress in expressive language can be seen in his ability to participate in a discussion with peers or the teacher. He should be able to express his opinion about a story and tell personal experiences with a logical sequence. Your child's expressive vocabulary should be significantly greater than it was in the beginning of the year as a result of frequent exposure to various kinds of books and interaction with more children and adults.
Your child probably entered kindergarten knowing how to write his name and maybe a few letters or numbers. At the end of the year, he will be able to write a complete sentence of at least four words. His sentences will contain some sight words -- frequently used words -- that he has learned. He will spell most of them correctly and will attempt to spell other words phonetically. Children will have different levels of writing mastery. Some might not be able to space properly between words or have neat handwriting, but most will know that words are written from left to right and that sentences should begin with an uppercase letter and end with a period.