Hi Christine, I was a member of the Jelbert Society and originally researched our ancestry back to John's father James. John was born in Gulval, but moved to Madron. The family also had land in Zennor parish. The three parishes, together with Morvah (often combined with or administered by Madron) were adjoining. When he died he was buried back in Gulval. The Gulval parish records at the time of John's birth were in Latin. Many local people may still have been speaking Cornish rather than English, but the English that they did speak would have been heavily accented (and sentence construction influenced by Cornish). Clerics may have come from outside the area and "interpreted" what they heard in terms of names, etc. Hence spellings, etc are very variable and you find everything between Jelbert to Gilbert for the family name (the Cornish took the French G and made it a J, as in Jelbert from Guilbert, Julian from Guillaume and Jennifer from Guinevere). Each time the name was written by someone it may have had a different spelling (as also spellings were not as important then, when few people could read or write anyway and the population was much smaller).
As another example of names, in John's profile is a reference to the stamping mill in Mulfra, in "Villenoy" in Madron, Villenoy was probably Vellanoweth in Cornish, which means New Mill (vellan = mill). There is still a hamlet called New Mill there today.
Happy to try to answer any question.
