This set of Matlab functions and data by Ondrej Glembek (firstname.lastname@example.org) is a simple tutorial of Joint Factor Analysis (JFA), as it was investigated at the JHU 2008 workshop http://www.clsp.jhu.edu/workshops/ws08/groups/rsrovc/.
The tutorial is based on Patrick Kenny's paper:
Kenny, P "Joint factor analysis of speaker and session variability: Theory and algorithms" - Technical report CRIM-06/08-13 Montreal, CRIM, 2005, http://www.crim.ca/perso/patrick.kenny/
especially on the simplified version of the training in:
Kenny, P., Ouellet, P., Dehak, N., Gupta, V., and Dumouchel, P. "A Study of Inter-Speaker Variability in Speaker Verification", IEEE Transactions on Audio, Speech and Language Processing, July 2008. http://www.crim.ca/perso/patrick.kenny/