Sojourner Truth, a slave freed in 1827 delivered this extemporaneous speech at the Women's Convention in Akron, Ohion, held in 1851. Interestingly, at the time that Truth gave her speech, it had no title and did not repotedly have the question "Ain't I woman?" in it once. The original speech was recorded after the convention which was attended mainly by abolitionists. Marius Robinson, an abolitionist himself and a newspaper editor recorded the words of Sojourner Truth; however, in 1881, the speech given was retold by Frances Gage. The insertion of the rhetorical question "ain't I woman?" and the editing of Truth's words to include more speech characteristics of Southern slaves was also added. This version has now become the historical standard.
So, in Gage's edition of Sojourner Truth's speech, the rhetorical question "ain't I woman?" is often repeated to add effect. In addition to this question, there are others that demand no answer either, such as "But shat's all this here talking about?" and "What's that got to do with women's rights or negroes' rights?" as well as "Where did your Christ come from?"