Letter Sound readers introduce the first 21 letter sounds. These readers have been written using a strictly controlled vocabulary. Text uses only decodable regular words (according to a week by week progression) along with 'tricky words'. Tricky words are words frequently used that are not decodable. Set includes 12 fiction readers, each with colorful illustrations. 12 Fiction readers Introduces first 21 letter sounds. Inside front shows exact progression. Point and say page for tricky words. Bright, colorful illustrations.