relative markers over time i am working on the history of relative markers in the spoken language from 1500 onwards , in british and american english . although there are plenty of studies of written data , i ' m having trouble finding diachronic studies of spoken data ( trial transcripts , etc . ) . i ' m particularly interested in the development of the standard & non-standard variants for personal subject restrictive relatives : who , what , which , zero , that , at , as ( as in ' i know a chap as ' ll do it for you ' ) . any references will be greatly appreciated , including quantitative synchronic studies of non-standard varieties . thanks !