To use voice command (i.e Automatic Speech Recognition) you must have all the required ASR files for the relevant map version as well as the Italian language SRD (Speech Recognition Data) file. Also in the case of using European maps you must have the entire map data for all EU loaded, if even one single map segment is missing you'll get that message. See this thread for more explanation generally, it's specifically referencing "American English" but the principle is the same for all other languages using Voice Command in capable devices: [Only registered and activated users can see links. ].