Jacques Guy is a French linguist, born in 1944 and living in Australia since 1968. He studied at the École des Langues Orientales (School of Oriental Languages, renamed since to the Institut national des langues et civilisations orientales) in Paris, France
In 1991 he proposed the 'Frogguy' transcription alphabet for the Voynich Manuscript.
A longer biography can be found on Wikipedia at 
He is also interested in Rongorongo.