The daiin

[Anton]

Thank you @Anton, do you mean I should move my remark there?

No, just a reference for the thread where we had a similar discussion and saw that even six repetitions in a row would not be something impossible.

Re daiin, here's is an interesting test. Locate a word in any more or less relevant language (Latin, German, Italian, Greek, Hebrew, whatever) which:

a) is quite frequent
b) forms another valid word when duplicated

That would be a potential match for daiin.