In the Swedish dub on the other hand, he is Ed and Scooby-Doo. This makes it an Actor Allusion for Stefan Frelander, who often voices a dumb or goofy person.
In Spain, Johnny is Private in The Penguins of Madagascar, which is interesting because his English (and German) voice actor, Oliver Feld, is Kowalski in said series.
Talking to Himself: The Danish dub played this straight in the Scooby-DooCross Over. Lars Thiesgaard, who regularly voices Scooby and Johnny, voiced both in that episode.