What is the theme of the "Ain't I a Woman" by Sojourner Truth? be specific

I would
define the overall theme of the speech as the acknowledgement of voice.  Truth's speech is one
given out of the voice of dissent, when she challenges the authority structure's understanding
of rights for all citizens and how there is a disproportionate treatment in this scheme towards
women, and women of color.  The idea of repeating "Ain't I a Woman" reminds the reader
of two realities.  The first is that women and their experiences were not fully acknowledged in
the legal, social, and political sensibilities.  The second is that the powerful voice of
dissent can never be silenced when injustice is present.  This resonates in the speech on both
gender and racial levels.  When Truth talks about working in the field and having "thirteen
children and sold them off to slavery," she is making very clear the reality in which she
operates as one that demands acknowledgement of voice on both the grounds of race and
gender.