Complex sentence: It is named after Ralph Nelson Elliott (1871--1948), an accountant who developed the concept in the 1930s: he proposed that market prices unfold in specific patterns, which practitioners today call Elliott waves.
Split into simpler sentences: It is named after Ralph Nelson Elliott (1871--1948), an accountant who developed the concept in the 1930s. He proposed that market prices unfold in specific patterns, which practitioners today call Elliott waves.