Around here our dispatch flips between plain english and 10-codes (sometimes they page a wreck out as a "2 vehicle accident" and other times as a 2 vehicle 10-50, sometimes they also page fires as a 10-70). Our department mostly uses plain english though, really the only 10-codes I can think of we ever use is 10-4, 10-84 is enroute, 10-23 is on scene,10-8 is back in service, 10-25 is disregard and instead of asking what someones 10-20 is it is often shortened to "what's your 20".

The sheriff's department here runs entirely on 10-codes though.

Our dispatch is with the Sheriff's Office so they like and use 10-codes. That means we have to know them and we use them . We drop the 10 codes when talking just between ourselves on scene. we use 10-7 for a death , not that we are fooling anyone. We generally only need to know about a dozen of the commonly 10 codes.

due to the confusion caused by code-speak  It has largely fallen by the wayside and is now discouraged in communication of the fire and police services.

and if you think about it if you are calling for help because a person is down what are the chances a new operator will know what the old codes mean? When seconds count do you want that person looking through a book to find what the code means?