There's more than German at play I think. Latin does not have a "J", thus names translated (back) from English or German that begin with a "J" will have an "I", such as in "Iohannes", or "Jesus" (and Judeaorum in "INRI"). I'd be interested in seeing more examples of this. The most convincing (and only non-religious) use of Latin in LR building I know of is the inscription on the Mansker rifle, "T. Simpson fecit".