Roman Britain was a multi-lingual society. To the indigenous, Celtic speaking population, Roman conquest introduced not only Latin but also Greek and the tongues of Rome's provinces, from the Celtic and Germanic languages of Britain’s neighbours to the Semitic languages of the Near East, such as Palmyrene. The curse tablets allow us to analyse the process of language change, especially among the civilian population of Roman Britain. Although ‘specialists’ must have played a part in composing and writing curses (see Curses and cursive - scribes), the many hands responsible for writing the tablets show that skills in Latin were not exclusive to priests or scribes (see Curses and cursive - scripts). Nor were they available only to individuals of a higher social status (see People, goods and gods - victims and wrongdoers).

The Latin of the tablets is of course very particular and peculiar. The texts are structured around exemplars from handbooks and an oral tradition of magical terms and formulae (see People, goods and gods - the workings of magic). There are also echoes of other specialist registers, the language of sacrifice (see Creating the curse -Writing the curse) and of Roman law (see Curses and cursive - scribes). Nevertheless the language of curses also shows influence from spoken and written Latin as it developed in the late Roman period. For example curses employ vocabulary outside the classical norm, such as manducare, ‘to eat’ (Uley 72) or baro, ‘man’, perhaps a loan word from Germanic languages (Brean Down). There also divergences in grammar and spelling. The main verb of a sentence often comes immediately after the subject rather than at the end (Uley 1). The doubling of s, for example in nissi for nisi (‘unless’ or ‘except’), is common in late Roman Latin (Uley 1). A distinctive dialect of British Latin has not yet been recognised in the tablets, although some uses may be different from those elsewhere (for example hospitium for house).

Many Roman Britons continued to speak the Celtic language(s) they had spoken before the conquest (the ancestor(s) of Welsh, Cornish and Breton) for everyday purposes. This is represented in names (see People, goods and gods - victims and wrongdoers) and in loanwords, for example gabatas, ‘plates’ (an unpublished Uley tablet). A handful of curse tablets from Bath and Uley have been very tentatively identified as being written in a Celtic language. Texts inscribed on lead in Celtic languages have however been found in graves and springs in south-west Gaul.

Greek is only so far known from a handful of inscriptions and graffiti in Britain, so the use of the Greek alphabet to write one Latin text at Uley is surprising. The use of Greek may, in this case, have been with a view to enhancing the magical effect of the text (see People, goods and gods - the workings of magic).