* It's likely an interjection: "Yo" is considered an interjection, a word that expresses a strong feeling or sudden emotion. Interjections are common across many languages, often evolving naturally within communities.
* Roots in African American Vernacular English (AAVE): "Yo" is heavily associated with AAVE and has been used for decades in African American communities. It has become widely adopted in mainstream culture.
* No singular origin story: There's no definitive historical record pointing to a specific person who invented the word "yo". It likely emerged from everyday language and became popular through use.
So, while we can't pinpoint a single inventor, "yo" is a word with a rich history and cultural significance, especially within African American culture.