[AStonesThrow]

Partly because that is how it’s spelled in Magic: the Gathering; the Ethereum founders say:

https://en.wikipedia.org/wiki/Ethereum#Founding_(2013%E2%80%...

Buterin chose the name Ethereum after browsing a list of elements from science fiction on Wikipedia.

https://en.wikipedia.org/wiki/List_of_fictional_elements,_ma...

Also, “Ethereum” looks like a misspelling to me; even though we’ve got “petroleum” and “linoleum” my instinct is to replace it with the more common “-ium” ending from the Periodic Table.

However, I have never been inclined to pronounce or spell “Dubai” with a diaresis, because it’s an Arabic word with a diphthong.

I am a native speaker of American English, second language Spanish; polyglot including proficiency in Latin, Italian, Greek, Sanskrit, and Semitic family.

[popol12]

Interesting, thanks. About Dubai, in french it would be pronounced "Du-bay" without the diaresis. It is not ambiguous in english though, but it never occurred to me !