Two assumptions frequently made about Latin in the medieval period are that it was simply the language of the Christian church and that the standard of Latin use was universally poor and not worthy of interest. However, the huge number and range of texts produced in Latin during this long period clearly demonstrate that despite times when education dropped in standard (as can happen at any period of history) or was limited to a small percentage of the population, those who were able to gain an education, primarily in monastic and cathedral schools, produced texts on a wide variety of subjects and in a wide variety of styles, often combining elements from classical learning with Biblical and patristic elements alongside elements from contemporary culture and personal experience, and reflecting many of the changes and dramas that occurred during the period.
If there is one way to characterize Medieval Latin, in fact, it is precisely its variety. In terms of the range of purposes for which Latin was employed, diversity was not new: as an everyday language previously, Latin had been used perfectly ordinarily for every function that language might be used for in speech and writing. Accordingly even in classical times the language had been diverse in its form too, usage differing according to the age or sex of the speaker, the topic of discourse, the register being used, and so on.
However, we know rather less than we might wish about this variation in Classical Latin because of the limits of the surviving evidence. Written texts can give only indirect hints of the diversity of spoken Latin, the range of functions carried out in writing rather than in speech was clearly different, and the greater distance in time means that more material has been lost or destroyed in the intervening years.
More important still, though, is the fact that from the first century BC Latin developed a highly standardized prestige form, namely Classical Latin, which was adopted as the variety of the language used in many of the functions carried out in writing. This means that the surviving texts typically reflect some attempt at conformity to this standard to a greater or lesser degree. Furthermore the texts that have survived through the ages into the modern world have tended to be the most highly regarded ones, being giants of literature, oratory, poetry, and the like, and these were most likely to conform to or even define this standard. Indeed their transmission and survival was encouraged precisely by their Classical Latin status.
Classical Latin, then, remained hugely influential as a standard for the language down to the medieval period and beyond. Great texts in that variety were read, and the sophistication of their language acknowledged in the writing of Latin in the Middle Ages, again with factors such as register and text type determining the extent to which writers would feel the need to attempt to conform to the Classical standard. The result is that alongside texts that try hard to meet the Classical norms we find many texts, especially ones that are not highly literary (e.g. accounts), in which the pressure of tradition and great literature as a model was not felt so strongly and other influences — such as the effect of the contemporary everyday languages — can be seen.
The ways in which writers used Latin free from the constraints of the Classical norms and the effects of this are the key to appreciating the diversity of Medieval Latin. There is a complexity that we can observe in written texts for the Middle Ages that we simply lack such good evidence for in the period when Latin was a native language. Far from being universally poor, we see the considerable skill of writers moulding the language to their needs.
There are many dimensions in which the linguistic diversity can be observed. The range of text types is clearly one, and we might note especially the development of rhythmic and rhyming verse, which is found as a new poetic form besides poetry written in the Classical Latin verse forms (based on syllable weight). However, there are some important linguistic differences that are frequently encountered in Medieval Latin that can make it look different from the Classical language, sometimes quite markedly so.
The most obvious difference in appearance between Medieval Latin and Classical Latin is in how words were spelled. Although Classical spellings were generally retained for inherited vocabulary, changes in pronunciation which had happened over the centuries — many the same as those which had led to the divergence of the everyday Romance languages from Latin and from each other — influenced the corresponding spelling of the words. Thus we often find ci before a vowel where the Classical spelling would have been ti (e.g racio for ratio), and the diphthongs ae and oe which had come to be pronounced the same as the simple e sound are often written e. (We also find as a result examples where ae or oe are written where the expected spelling would be just e.) Other alternations in spelling arising from changes in pronunciation are the interchange of b and v, the insertion or deletion of h, the use of single consonants for double ones (and vice versa), and the substitution of y for i. Sometimes spellings were also influenced by the pronunciation of a word in the everyday local language related to or derived from the Latin word (or thought to have been so).
For new vocabulary the writers often faced the challenge of having no certain model to follow. While writers of Latin still had some sense of words having ‘a spelling’, inherited from the standardized Classical language, this principle was already undermined by variation, and for borrowed vocabulary, the source language (Old or Middle English, Anglo-Norman French, etc.) typically had no single standard spelling that could be borrowed. Indeed, the word in the source language would usually have had slightly different pronunciations in different areas in any case. Moreover, frequently the borrowed vocabulary would contain sounds not found in inherited Latin vocabulary, such as the ‘sh’ sound of English and French. Writers would therefore use the Latin alphabet as best they could to represent the words they wished to write. We find some extreme examples in British Medieval Latin of the resulting variation, such as ‘maeremium’ (‘timber’, borrowed from Anglo-Norman merim and related words, originally derived from Late Latin materiamen) which is attested in more than 50 different spellings (e.g. maerremium, mahermium, maisremium, etc.).
Finally, we must remember that writing materials were expensive in the Middle Ages, and it was extremely common for scribes to use abbreviations. Typically abbreviation was indicated by some form of mark or stroke made through, above, or immediately following the letter preceding the position of the omitted letter(s). Many modern editions of texts ‘expand’ such abbreviations to make reading the texts easier, but the correct way to expand such forms is not always clear, particularly at the end of a word, where scribes often seem to have used abbreviation as a convenient way to avoid giving a borrowed word an explicit (grammatical) ending.
The most important differences in the grammar of Medieval Latin again lie in the greater flexibility allowed in the use of the various forms of words and constructions, alongside the general continuation of most of the Classical grammatical system.
The inflectional system was not always used as consistently or rigidly as in Classical Latin. Thus, prepositions and verbs which would have been followed by a noun or adjective in one case in Classical Latin are not uncommonly found followed by a word in a different case. Similarly, conjunctions which in Classical Latin would have been followed by a verb in the subjunctive mood might be found followed by a verb in the indicative (or vice versa). Also, verbs which had been deponent in Classical Latin (i.e. had passive forms but active meanings) are often found used in active forms (in the same meanings).
New constructions also arose, in some instances used as an alternative to existing ones. Most significant among these was the increase in use of the indirect statement construction consisting of quod or quia followed by a clause with a finite verb (sometimes indicative, sometimes subjunctive) instead of the Classical way of expressing the same meaning (using the accusative and infinitive construction). The quod or quia construction had in fact already existed in the Classical language, but only in restricted circumstances, and it rose to prominence not only in Medieval Latin but also in the Romance languages (cf. modern French je dis que …).
The DMLBS naturally concentrates on the vocabulary of the language and highlights the differences (or, rather, innovations) in this area. It is easy in this regard to overlook the simple fact that the vast majority of Medieval Latin vocabulary is vocabulary inherited from earlier stages of the language and used in ways and in meanings that were a normal part of those earlier periods' usage.
Still, we see that inherited words frequently do develop or show new meanings of various kinds, including restrictions of existing meanings, metaphorical and metonymic extensions of existing meanings, and meanings arising from connections with other related or similar words. For instance, we find regulariter in the sense of ‘in accordance with a monastic rule’, pupula can refer to the eye and a disease of the eye as well as to just the pupil, and purare ‘to free from dirt’ is found more generally than just the ceremonial context in the Classical evidence. The new meanings are usually found in addition to the continuation of one or more Classical ones; less often we find such words used only in new senses.
Sometimes the changes in meaning even affected grammatical words, and as a result the grammar of the language has the appearance of having changed: for instance, we frequently find the pronouns se (‘himself, herself, itself’) and eum (‘him etc.’) interchanged.
Writers were also able to coin new words. Sometimes these were based on existing Latin vocabulary, such as deriving new nouns in -tio from verbs in order to denote the ‘act or process’ of the verb (and often also the ‘product or result’ too), or adverbs from existing adjectives (e.g. querule ‘plaintively’ from querulus ‘plaintive’).
The most striking type of new coinage, though, was of course the borrowed vocabulary. When a writer came across something to be expressed for which there was no existing Latin word (e.g. a new invention or social position) or the writer did not know the right Latin word, the typical response was to adopt and adapt a word from that writer's native vocabulary, making minimal changes as necessary to fit it into the Latin grammatical system. Such changes might include adding a suitable inflectional ending, normally that of the most common pattern for that kind of word (e.g. the first conjugation endings for a verb).