Phonograms are the most foundational element of learning to read and spell. The 70 basic phonograms described by Dr. Orton are the most basic elements of written English.
A phonogram, literally speaking, is a picture of a sound. Each one is a letter or combination of letters, such as m, e, tch, or ou, that represents one or more sounds in English. Knowing the phonograms is key to learning how to decode written English.
Since spoken English is made up of 45 sounds, the 26 letters of the Latin alphabet are inadequate to describe these sounds. Therefore, additional multi-letter phonograms are used to account for sounds such as /ch/, /ow/, /th/, and /oi/. Knowing the written representations of each sound is essential to learning to read and spell.
In addition, English is a complex language; 27 of the phonograms represent more than one sound. It is vital to teach all the sounds of each phonogram so that students know all the sounds made by each. This prevents students from needing to treat countless words as sight words and provides a more accurate description of the language.