The word "helicopter" isn't a compound of "heli" and "copter", but "helico" and "pter".

@SW-User what are the English syllable boundaries? In Greek we usually put -o- when we connect words.

@HannibalAteMeOut Syllable boundaries are not always clearly defined, but there are phonotactic rules that govern them. For example, an English syllable cannot begin with /pt/ (but this is an acceptable syllable onset in Greek). Thus the syllable boundaries of "helicopter" would be he.li.cop.ter, making it appear as if it's made up of two parts: heli- and -copter.

@SW-User ohh I see, thanks!

@SW-User well that seemed a little harsh 🤔