Dahalo languageDahalo is an endangered Cushitic language spoken by around 500-600 Dahalo people on the coast of Kenya, near the mouth of the Tana River. Dahalo is unusual among the world's languages in using all four airstream mechanisms found in human language - clicks, implosives, ejectives, and regular consonants. While the language is known primarily as “Dahalo” to linguists, the term itself is an exonym supposedly used by Aweer-speakers that itself essentially means “stupid” or “worthless”.
Consonant voicing and devoicingIn phonology, voicing (or sonorization) is a sound change where a voiceless consonant becomes voiced due to the influence of its phonological environment; shift in the opposite direction is referred to as devoicing or desonorization. Most commonly, the change is a result of sound assimilation with an adjacent sound of opposite voicing, but it can also occur word-finally or in contact with a specific vowel. For example, the English suffix -s is pronounced [s] when it follows a voiceless phoneme (cats), and [z] when it follows a voiced phoneme (dogs).
GlottisThe glottis is the opening between the vocal folds (the rima glottidis). The glottis is crucial in producing vowels and voiced consonants. From Ancient Greek γλωττίς (glōttís), derived from γλῶττα (glôtta), variant of γλῶσσα (glôssa, "tongue"). Phonation As the vocal folds vibrate, the resulting vibration produces a "buzzing" quality to the speech, called voice or voicing or pronunciation. Sound production that involves moving the vocal folds close together is called glottal. English has a voiceless glottal transition spelled "h".