Unicorns differ from humans and giants in their organs of speech. Some of the differences are quantitative, others qualitative: the roof of the mouth of a unicorn is longer than that of a human, and permits more places of articulation to be distinguished. In the Shunhaurat, tonality is rare in human languages; in unicorn languages it is effectively ubiquitous as unicorns use their hornsounds extensively (outside of trade pidgins), a qualitative difference representing a formidable obstacle to humans undertaking to speak unicorn languages. Human tonal languages often involve pitch contour, a feature that does not appear in unicorn languages as a contrasting feature. Most unicorns do not have fine temporal control over phonation, and their languages do not distinguish phonemes based on voicing. Pitch control over the larynx is also wanting. Most unicorn languages only feature stops at the beginning of syllables.
Unicorn languages do not distinguish vowels by rounding. No unicorn language distinguishes more than six vowels, and they commonly have far fewer, usually two or three. Diphthongs are uncommon, though unicorns do not have exceptional difficulty acquiring them. Unicorn languages do not have laterals.
The unicorn horn has five sphincters, the closing of which determine its acoustical length and hence the pitch at which it sounds. The sphincters close sequentially. A chord may be formed with the vibration of the larynx, a valued technical skill appearing in unicorn songs. Hornsounds are noted as <1> ... <5>; the sphincters being an inherently quantized feature (unlike places of articulation in the tongue), the notation is universal for all unicorn languages. Some unicorn languages feature a sort of plosive articulated by raising the pressure of the corunal sinus, closing a sphincter, lowering the pressure of the sinus, and abruptly opening the sphincter. This is noted as, e.g. <1'>. Hornsounds can be concurrently articulated with oral sounds, and sequential articulation is marked with a dash, e.g. <s-2en>.
The use of hornsounds often has a grammatical or productive morphological role in unicorn languages, though in some it is simply another sound of the language serving to distinguish lexical items.