In the mid-19th century, tap dancing was born when the early African Americans (most of them slaves), combined their footwork with what other type of dance:

 Tap dancing was born when the early African Americans (most of them slaves), combined their footwork with dance of Irish servants.

Explanation:

Tap dancing originated when African Americans combined their footwork with clog dancing from British isles. Tap dancing was started by African dancers most of them were slaves in early America.

The Tap dancers were called as Levee dancers. Dance reduces their pain of suffering. In the Tap dance, the dancer wears the shoes with heels and dances by producing rhythmic sound by tapping the toes. African slaves observed the Irish servants while dancing and combine their dance with them to produce Tap dancing.

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