A Diachronic Analysis of Latinisms in the Decisions of the UK Supreme Court

Latinism is a form of legalese often resorted to in many legal documents, such as contracts, statutes, and court decisions. Exponents of plain language have long encouraged the use of plain terminology in legal texts and the replacement of archaic terms (among which are Latin expressions) with more modern or common ones. This paper aims at exploring to what extent the UK Supreme Court used Law Latin in its decisions from 2012 to 2023. At the same time, it wishes to unveil whether (some of) the plain English equivalents suggested in the literature took their place. For these purposes, six Latin formulae are focused on (i.e., a fortiori, ab initio, de jure, inter alia, mens rea, mutatis mutandis, and sui generis). By consulting the BAILII interface and the UK Case Law National Archives, this paper investigates whether such expressions (and their plain English equivalents) are mentioned in the Court judgments. The findings highlight an infrequent use of Latinisms in the Court decisions, with the exception of inter alia. Plain English equivalents, however, are not applied consistently, and they do not seem to have progressively and systematically replaced their more archaic counterparts. Plain expressions appear in the Court decisions, but either not thoroughly, or with lexical/syntactical discrepancies and differences in meanings or usages which would not qualify them as full “replacements”.