I notice people in mainland China use abbreviation for almost all titles.
Example:
習總裁 --> 习总
郎(平)教練 --> 郎教
任隊長 --> 任隊
This kind of abbreviation even appears in Hong Kong's TV dramas.
Example:
王法官 --> 王官
張大狀(大律師) --> 張狀
I personally think shortening a two-character word to a single-character one is too casual and may cause confusion (I am sure we will only find 习总裁 and not 习总 in official documents).
Notice:
习总 and 杂种 sound the same in Cantonese
任隊 in Cantonese sounds like "allow to stab at will"
王官 and 皇冠 sound the same in Cantonese
任总督--> 任督 make people think of 任督二脉 and sounds like "allow to poke at will" in Cantonese
Question: Is not abbreviating titles in casual conversation considered normal in Mainland? (in other words, I wouldn't give it away that I was not a mainland Chinese by saying 郎(平)教練 instead of 郎教)