Decoding is the ability to apply your knowledge of letter-sound relationships, including knowledge of letter patterns, to correctly pronounce written words. Understanding these relationships gives children the ability to recognize familiar words quickly and to figure out words they haven't seen before. Although children may sometimes figure out some of these relationships on their own, most children benefit from explicit instruction in this area. Phonics is one approach to reading instruction that teaches students the principles of letter-sound relationships, how to sound out words, and exceptions to the principles.