It's an Odd Coincidence, Is It Not?

I am not the Japanese scholor that Driver-san is but I did do a few units of Pimsleur's Conversational Japanese.  One thing I learned was that if you add the "nay" sound to a word in Japanese it becomes a question of the form "is it not?". So "here is the car" becomes "isn't the car here?" by adding this sound. 

I found this very curious because I took Latin in high school (from a Jesuit named Father Crane whom, we were all convinced, had learned Latin as a child in Ancient Rome) and there was a similar construct in Latin. Well, not so much "similar" as "identical". If you add the letters "ne" (pronounced in Latin "nay")  to a word it expressed the exact same idea as the "nay" sound in Japanese. That is, "is it not?" 

This is either the mother of all coincidences (that two so very different languages should have the same exact sound used in the exactly the same way) or there must be some cross over from Latin to Japanese. That would be very strange, would it not, for the Romans to influence the Japanese?  I don't think anything like that happened in history.

But Japan was visited by Portuguese Jesuit priests. Portuguese is a "romance language" which means that it is heavily influenced by Latin. I have no idea if Portuguese has the "ne" construct in it but it sounds plausible to me. Maybe the Japanese got this very convenient verbal trick from the Portuguese who got it from the Romans. 

So perhaps both the Japanese and I learned Latin from Jesuits! 

An odd coincidence, is it not?