This package installs only the fortune cookie data, not the scripts in the upstream tarball.
Environment variables such as LANG are ignored by the new (internationalized) fortune-mod
package. Instead you should define aliases or wrapper scripts pointing fortune
to the subdirectory where these cookies are stored, for example:

alias spruch='fortune de/{anekdoten,computer,doppelsinnig,gedichte,mathematiker,sprueche,tips,witze,zitate}'
alias rezept='fortune de/{beilagen,brot,dessert,huhn,kalt,kuchen,plaetzchen,suppe,salat,sauce,vorspeise}'