The pronunciation of 'Ni O' can be a bit tricky depending on the context! If it's Japanese—like the term '二王' (two kings) or a name—it's closer to 'nee oh,' with both syllables crisp and even. The 'i' in 'Ni' isn't drawn out like in English 'knee'; it's shorter. For 'O,' think of the Spanish 'o' in 'no'—pure and unrounded.
Now, if it's from Mandarin (like '你哦,' meaning 'you oh'), 'Ni' is third tone (dipping, like a hesitant 'nee?'), and 'O' is neutral, almost like a soft 'uh.' I messed this up for ages until a friend corrected me mid-convo. Watching native speakers in dramas or YouTube clips helped me nail the rhythm—it’s all about that tonal flow.