Edit Displayed User Names
It would be more convenient if we could customize user display name to allow better identification of individuals. For external contacts, email addresses are currently displayed and cannot be edited to reflect the contact's name.
Lars Roth commented
Please see and vote also this idea:
ベルシヤウ ニイル . commented
Agreed! This is vital when using this in an EFL university environment when teachers are unable to read the student's name. I am in Japan and some of the advanced kanji in names is impossible. I need to be able to alter the display names.