> During the First World War , the Italian Army used people from Sardegna (an island) for
radio-transmitting , because their dialect is impossible to be understood even from other Italian
people, so it was safe against the possibility of interception.

This is very interesting. The Irish army serving in Lebanon under the UN use Gaelic (Irish) exclusively for radio transmissions because the Irish language is one of the most difficult languages to understand. However, in the early years of the war in Lebanon, Israeli radio units were taught Irish as a second language with the sole view of intercepting and decoding these Irish and UN transmissions.