Bonjour Danielle,
Apparently this has nothing to do with pronunciation at all. I have traced this person's origins back to an Ancestry.com family tree that cites this work:
Quebec Genealogical Dictionary for Canadian Families (Tanguay Collection): 1608-1890,
On Vol. 5, Sect. 1, pg. 91 of this alphabetically-arranged dictionary: "Joa-Leh," under "Laigu," one of the "variations et surnoms" is "Leillu". So the dictionary cites Rene Charles... as Rene Charles Laigu under the year 1709 (1st marriage to Marie Royer). That is the origin of the confusion. It then goes on to name his parents as Isaac Laigu & Therese Doucet from Alencon, Diocese de Seez, Orne, Normandie, France. and the next page gives more on his descendants in Quebec (Rene Charles was the emigrant; parents apparently remained in France). Alencon & Seez have accents that I cannot repeat from this computer.
This is from the Swantek, Ruel, Snyder Ackerman (Stefancich) Family Tree on Ancestry.com = Tree 83614505 Person 150041110581 etc.
I found this on Ancestrylibrary.com as I am not an Ancestry.com member myself.
Hope this helps - I changed Isaac's profile to Leillu-2 and give full source references there.
Bien cordialement
Chet Snow-2128