That's unfortunate. Of couse I can just decide to ignore instructions if I know the route. But then I don't need routing at all. If I don't know the route then unexpectedly ending up on an S2 trail is not an option. I might be riding my road bike or I may have company that can't handle S2. I'll have to plan the route in advance anyway, but I don't see me remembering which instructions to follow and which to ignore on a 100km tour. So planning the route the way I intend to ride it is imperative.
I found that espeak can use German pronounciation if one provides the option -vde with the string it should read. The result is not pleasant but it's understandable. Adding something like +m3 or +f2 to the option even lets one pick one of four male or two female voices. Although I must say that the different voices of one gender all sound the same or at least very similar. So it would be nice if one could tell modrana to use that switch.