I and Y in French

[Robert Johnson]

I see certain relationship between these two characters in French (both are i, although one is i Greek), similar pronunciation: roi, Geoffroy, etc.

 

So what's the history related to the usage of these letters? When is i used and when is y used?

[Neil Coffey]

In current usage, "y" is basically not used in these word-final positions, and "i" would be used instead.

However, up until around the 18th century, words such as "lui", "toi", "roi", "ai" etc were written "luy", "toy", "roy", "ay" etc. Hence, for example, the surname "Leroy", or other alternations that you see in names such as "Geoffroi" ~ "Geoffroy".

If you're interested more in the timing of this change, then you might want to have a look at different editions of dictionaries from the 1700s/1800s to see when different dictionaries adopted the "new" spellings.

[Robert Johnson]

Thank you so much, Neil, for the interesting and knowledgeable reply.

My curiosity about these letters also same from words like 'royal'. I knew it was related to 'roi' but why i in roi changes to y in royal? Is there a rule for this transformation?

[franci.discendum]

Y is pronounced like a double I. Example : loyer is pronounced loi-ier [lwaje] or payer is pronounced pai-ier [peje].