The linguistic diversity of medieval Britain means that we find not only that many British authors also wrote in languages other than Latin but we find many examples of multilingual texts. The most obvious and common examples of these are texts that incorporate interspersed words of a second language, e.g. in accounts where the structure and prices are given in Latin but the individual items purchased are often recorded in English (or using the English word with a mark to indicate the omission of an appropriate Latin ending). Such texts reveal the continuum between what is clearly vernacular vocabulary borrowed into Latin with Latin grammar and forms and what is really a vernacular word used unaltered in a Latin context.
In some instances, however, we find more intentionally multilingual texts, such as parallel versions of the same text in different languages or explicit translations. We also find more focused multilingual evidence such as notes or ‘glosses’ written into the margins of texts, typically in another language, to assist the reader of the text; these accumulated glosses would themselves sometimes be compiled into independent vocabulary lists and be preserved separately from the texts for which they were originally made.
Important too are works specifically written about language and its use, whether in terms of its style, its grammar, or its vocabulary.
We may perhaps usefully divide the examples where we have parallel texts into two groups, those for which the Latin text is the original (and the translation derived from it) and those translated into Latin. We find examples of both types among the evidence for British Medieval Latin. Indeed, a wide range of text types were the subject of translation in one direction or the other. At one end of the spectrum, for instance, we find the presentation of the Anglo-Saxon Chronicle in Latin in one of its versions, while at the other we find the early 14th century Latin translation of the Ancrene Riwle, a monastic rule for contemplative nuns.
English was not the only language to be translated into Latin. Across Europe the Middle Ages saw a blossoming of translations into Latin of philosophical, scientific, and technical material from Greek and Arabic sources, many made by notable British scholars, such as Adelard of Bath and Robert of Chester's translations of mathematical texts.
The same fields of philosophy and especially science also gave rise to translations from Latin: in particular we should note the work of the prolific 14th century translator John Trevisa, who among his many translations, produced an English version of Bartholomaeus Anglicus' encyclopedic work De proprietatibus rerum.
In translations, as in all other aspects of Latin use in the medieval period, we see the vitality and importance of the language.
Specifically linguistic texts provide an important different perspective on the Latin of medieval Britain. Even in ancient times, when Latin had been a native language, writers such as Varro and Quintilian had written about the language, at least partly as a guide to its use. As the Latin language gradually became differentiated from the evolving everyday languages of Western Europe, so users of Latin increasingly felt the need for guidance on the language, and this was true in Britain also. As well as a range of surviving texts that reflect this need we also find the medieval continuation of the tradition of linguistic discussion for its own sake.
Texts concerned with linguistic matters can be especially valuable for lexicographers because they explicitly comment on meaning or usage, but they also come with particular problems arising from the difference between what language users think they do (or should do) and what those language users actually do with their language. In addition, while lexicographers normally rely quite heavily on the context in which a word is used in order to be able to deduce its meaning etc., in linguistic texts words are often presented with their comment completely divorced from any particular context of use, making such examples difficult to assign to specific senses.
Alongside rhetorical and poetic handbooks we find works on Latin spelling (such as those by Bede and Alcuin) and grammar (such as that by Ælfric, but note also interest in other languages, such as Bacon's grammatical works on Greek and Hebrew).
Our most extensive sources, however, relate to vocabulary. We find glosses in Old English and in Latin on the manuscripts of the works of Aldhelm. The usefulness of these for reading their particular texts was apparent in the Middle Ages, as was their possible wider value. We thus find the ancestors of modern dictionaries in collections of glosses copied separately from their original texts. These typically present the word being glossed (the lemma) and a brief translation equivalent or explanation or description of the meaning, in Latin or a vernacular language. At first presented in the order in which the words appeared in the text being glossed (and with the words in the form used in that text), these lists were evidently repeatedly copied and circulated independently from those texts, accruing additions, amendments, deletions and often, eventually, being reordered thematically and/or alphabetically (at first only by their initial letter, later by the first two or three letters). We have surviving examples dating back well into the Anglo-Saxon period (in which the Old English glosses themselves are now often as contentious and difficult to interpret as the Latin they explain), and a continuous range of successors down to the sixteenth century, just decades before Du Cange prepared the first substantial dictionary of Medieval Latin.
Other types of collection of vocabulary survive too, for instance lists of items associated with particular fields, sometimes as a base text for glossing (e.g. works by John of Garland and Alexander Neckam). Plant names were a particularly frequent domain for treatment as a list with more or less descriptive, explanatory or identificatory notes (e.g. Alphita and the Sinonoma Barholomei). Finally we might note the Etymologies of Osbern of Gloucester, compiling (and perhaps inventing) lists of related words and their meanings, following partly in the genre of Isidore of Seville.
Although not strictly intended as glossary texts themselves, very many technical texts also set out to give information about technical words in their particular fields. For instance we find discussion in musical works about the different lengths of notes in which the meaning of particular terms is identified and the possibility of new names or terms for these is explored; similarly we find discussions about definitions and meanings in texts about legal matters, as well as in philosophy, science, and theology.
Sometimes, however, we have to wonder — as with glossaries and etymologies — whether the exploration or definition of vocabulary is a purely academic exercise of inventiveness on the part of the writer: we have many examples of such terms that in our evidence effectively appear only in discussions of their definitions or the like and do not seem to be used in any ‘real’ live context.