The documentary (non-literary) Greek material of Egypt (papyri, ostraca, inscriptions), as well as additional literary and semi-literary comparanda, will be collated and analysed to contextualise the processes of change taking place in non-literary environments during the Roman and early Byzantine periods. This study will also apply select Atticistic dicta to the same evidence. I will analyse the data collected to determine how far Atticistic usages (prescribed forms) penetrated the lexical choice of writers of non-literary texts, and to ascertain, more generally, the reliability of innovative words (proscribed forms) in the same documents as evidence for linguistic change and diglossic divergence. I will also develop a theoretical framework that reconciles the notion of register with social factors (situational characteristics, functional areas), so that lexical changes might be tracked in as close detail as possible.