 Jackson drew conclusions about the nature of British Latin from examining Latin loanwords that had passed into the British Celtic languages.From the 1970s John Mann, Eric P. Hamp and others used what Mann called "the sub-literary tradition" in inscriptions to identify spoken British Latin usage.In the 1980s, Colin Smith used stone inscriptions in particular in this way, although much of what Smith has written has become out of date as a result of the large number of Latin inscriptions found in Britain in recent years.