||The stress put on the marked syllable is drawn out. Always pronounced LONG. In theory the voice goes up, then down again, leading to a singsong sort of intonation. Which is difficult to do unless a 4th century b.C. Athenian comes along and lets us imitate him. I may not do it all that well.|
But keep in mind that it most probably SHOULD be pitch going up, then down again. Which will explain why words ending in stressed -ων take an acute accent, unless they are genitive plural or otherwise the result of a contraction. In which case they DO take a circumflex.
As we'll see later on. Just keep an open mind about the seeming vagaries of pronunciation and spelling.