Newcomers to Voynich studies should avoid supposing the language of Voynichese will be the native language of its scribe. Should Voynichese prove, say, to be enciphered German, the nature of medieval society means that the writer might yet be a Spaniard, an Italian, a North African Muslim or a Jew of Provence.
Monolingualism is fairly rare before the modern era, especially in people who had learned to write well.
Knowledge of a vernacular tongue (such as French), can be expected supplemented by acquaintance with an ecclesiastical language (such as Latin, or Hebrew), and one or more neighbouring languages or dialects (in this case, perhaps English and/or Provençal. A smattering or more of trading tongues might be needed if the person engaged in trade – a weaver might need some Netherlandish, for example.
To assume none save Greeks spoke Greek, or that a Greek would speak nothing else is surely common for modern monolingual English speakers, but it does not agree with what we know of the fifteenth century and earlier.
One hears of persons in the great trading centres who had six languages, while formally trained scholars might have still more, at various levels of proficiency. In the seventeenth century, Athanasius Kircher seems to have picked up languages as a walker does burs, but popular histories of the fifteenth century show also that members of the French and Italian courts could switch from one language to another as a kind of parlour game, or as a form of politeness to the latest diplomatic visitor.
In addition, conquests’ ebb and flow led in some cases to languages or dialects including forms and items of vocabulary from a number of separate tongues. As example, consider modern Maltese:
Maltese is part of the family Hamito-Semitic also called Afro-Asiatic languages. Within this family, it is part of the group of Semitic languages. Current Maltese, wh[ich] is the heir of Arabic Maltese is historically part of the Sicilian-Arabic, with siqili (Arabic Sicilian, now defunct), one of the dialects Ifriqiyan Arab, relexification from superstrate mainly Sicilian and Italian, to a lesser extent French and more recently English is clear, from the twentieth century, a standard language that has regional varieties or topolectes.
In morphological typology, Maltese is an inflected language that combines bending with internal chips of Arabic to terminations of synthetic languages, Sicilian and Italian. In syntactic typology, Maltese is an SVO language like that is to say that the normal order of the sentence is subject – verb – object.