The "i" Placeholder

The "i" Placeholder
When creating pinyin combinations be wary of the 'i' final. 


Ordinarily, 'i' is pronounced "eee." However, when paired with specific groups of initials, 'i' loses its sound and acts only as a placeholder for the sound of the initial. 


The following initials for which this rule applies are:  
          - zh, ch, sh, r, z, c, s


Example:  "bi" vs "zhi"
I think this website will help to better illustrate my point.
First create the pinyin syllable "bi" and then create the pinyin syllable "zhi."


Notice that despite the fact that both "bi" and "zhi" contain the "i" final, only the "bi" pinyin syllable contains the "eee" sound, whereas the pronunciation of the "zhi" syllable is the "zh" sound.