Human languages represent very complex coding systems that can be decoded by the human brain after a long acquisition phase. In their acoustic form, human languages can be expressed through different natural speech types. Modal speech is the most common one but several other registers have evolved around the world to enable interlocutors to speak from far. This chapter first provides a large overview of the limits of modal speech for distance communication and lists the major acoustic constraints that interfere with spoken communications in rural outdoor settings. Next, it describes how speech has been naturally adapted to these constraints in different populations by transforming the sounds of spoken languages in shouted speech, whistled speech, or drummed speech. These three registers represent different ways of coding the same linguistic targets as modal speech. Their comparison in a wide variety of languages of the world highlights the great productive and perceptual flexibility of humans to transmit messages of linguistic attitude for telecommunication purposes in natural surroundings.