What is "initial teaching alphabet"

The Initial Teaching Alphabet (I.T.A. or i.t.a.) is a variant of the Latin alphabet developed by Sir James Pitman (the grandson of Sir Isaac Pitman, inventor of a system of shorthand) in the early 1960s. It was not intended to be a strictly phonetic transcription of English sounds, or a spelling reform for English as such, but instead a practical simplified writing system which could be used to teach English-speaking children to read more easily than can be done with traditional orthography. After children had learned to read using I.T.A., they would then eventually move on to learn standard English spelling. Although it achieved a certain degree of popularity in the 1960s, it has fallen into disuse.