Siyanni is likely a modern elaborated name in African-diaspora style, valued more for sound than fixed etymology.
Siyanni flows with the musical resonance of names drawn from the Indigenous traditions of the Great Plains, most recognizably echoing Cheyenne — the name of a proud Algonquian-speaking people whose homeland stretched across what is now Colorado, Wyoming, and Kansas. The Cheyenne called themselves *Tsėhéstȧhese* ("those who are alike" or "our people"), but the exonym Cheyenne, likely derived from a Lakota Sioux term, entered the English record in the eighteenth century and eventually became a given name in American usage, particularly in the Western states where the nation's history left deep marks on the landscape and the culture.
Siyanni is best understood as a phonetic reimagining of that tradition — preserving the syllabic melody of Cheyenne while giving it a new visual form that emphasizes its feminine lyricism. The *-anni* suffix echoes Italian and Spanish feminine endings, lending the name a cross-cultural warmth that makes it feel both Indigenous-inspired and universally accessible. Names of this type — drawing on the sound-world of Indigenous American languages while adapting them for contemporary use — reflect a broader cultural movement to honor the pre-colonial naming heritage of North America. For a child named Siyanni, the name carries the windswept poetry of the Plains: it sounds like movement, like open sky, like something that has traveled a long way to arrive.