The manuscript uses a language that arose from a blend of spoken Latin, or Vulgar Latin, and other languages across the Mediterranean during the early Medieval period following the collapse of the Roman Empire.
It is therefore a mix of words which have evolved into the many Romance languages, including Italian. For example the phrase 'orla la' translating as 'on the edge or losing patience' used to describe a woman in the children's bath scene may well be the root of the French phrase 'oh la la.'
Likewise the world for slippery or oiled, written as 'oleios' in the manuscript survives as 'oleio' in Portugeuse while 'tolora' meaning foolish, is still present in Catalan as 'tozos.'
Dr Cheshire said: "The language is proto-Romance. This is the only known example, because it was the language of the common people and therefore not used in official documents.
"On Ischia, the language was still used in geographical and cultural isolation, so it was used for the manuscript even though Queen Maria was fluent in Latin."
Solving the riddle has opened a door into the daily lives of women in Medieval Europe. The manuscript is a compendium of herbal remedies, therapeutic bathing and astrological readings concerning matters of the female mind and body, reproduction and parenting.
It gives advice on how to prevent infections in pregnancy, or even how to induce an abortion, revealing a muddle of Catholic and Pagan beliefs. The phrase 'omor néna' meaning 'dead baby' still survives in the Romanian word 'omor' meaning 'to murder'.
The text also encourages using Mediterranean sea holly as an antiseptic but warns 'pesaut om eos e peor e peia t' (Apologies people, they have the worst sting).
And there is a fold-out pictorial map within the pages that details a rescue mission led by Queen Maria to save the survivors of a volcanic eruption which began on 4th February 1444.
The map shows a representation of heaven as a castle in the sky, where the deceased are imagined to travel.
The manuscript was so tough to crack because it lacked traditional punctuation, instead using variations of characters to indicate grammar and phonetic accents.
Dr Cheshire added: "I experienced a series of 'eureka' moments whilst deciphering the code, followed by a sense of disbelief and excitement when I realised the magnitude of the achievement, both in terms of its linguistic importance and the revelations about the origin and content of the manuscript.
"It is no exaggeration to say this work represents one of the most important developments to date in Romance linguistics."
The Voynich manuscript, which has been carbon-dated to the mid-fifteenth century, is named after Wilfrid Voynich, a Polish book dealer, who bought it in 1912, the same year that Castello Aragonese changed hands, suggesting it may have been part of house clearance.
It is currently housed at Yale University, in the Beinecke Library of rare books and manuscripts. As well as Turing, the FBI also tried to crack the manuscript during the Cold War, thinking it may have been Communist propaganda.
The research was published in the journal Romance Studies.