About Rudolf Flesch
Rudolf Franz Flesch was an Austrian-born naturalized American author, and also a readability expert and writing consultant who was a vigorous proponent of plain English in the United States. He created the Flesch Reading Ease test and was co-creator of the Flesch–Kincaid readability tests. Flesch advocated use of phonics rather than sight reading to enable students to sound-out unfamiliar words.
Biography source:
Wikipedia