Claudia Hartmann is an approved teacher of speaking, breathing and voice coordination using the method of Schlaffhorst-Andersen. She is also a voice trainer approved by Linklater and therapist for functional breathing and speaking techniques after Dr. Med. Parow. 

Claudia Hartmann is also an actress. Her longstanding activity as actress took place among others at Young Theatre Bonn, Acting House Bochum and Salzburg Festivals.

In 1999, after her formation as a teacher of speaking, breathing and voice coordination, she worked as voice therapist in Witten and as teacher at the Music University Detmold, at private acting schools and at the Schlaffhorst-Andersen school in Bad Nenndorf.

 In 2002 she started her career as a teacher in the field of speaking techniques at the University of Arts Folkwang in Essen, in the acting field for the same university in Bochum and in the field of scene performances at the University of Music and Performing Arts in Frankfurt. She also supported actors of the State Theatre Münster in developing their voice coordination.  

She regularly offered seminars for professional formation and developing.  

She was member of many performances and literary, dance and theatre projects at private and state theatres, in museums and public spaces.