In the PLA, people seldom called each other by rank titles. Even superiors were mostly addressed as "boss" or "chief." Why not use ranks titles? Partly because they were so complicated. You'd require a virtual slide rule to calculate somebody's service, branch, grade, career track, and job duties before you'd know with confidence his correct courtesy title. Get that wrong and ... well, it was safer just to say "comrade."
But that was before Comrade Technical Senior Colonel Jason T. Clower came along to demystify it all for you! I have devised the world's fastest method for teaching you the old-school PLA's extravagantly overwrought system of courtesy titles.
All you need is a brain supple enough to memorize irregular Latin demonstrative pronouns, and this video will do the rest!