REPORT pgarner:rr08-03/IDIAP A Weighted Finite State Transducer tutorial Garner, Philip N. EXTERNAL http://publications.idiap.ch/attachments/reports/2008/pgarner-idiap-com-08-03.pdf PUBLIC Idiap-Com-03-2008 2008 IDIAP The concepts of WFSTs are summarised, including structural and stochastic optimisations. A typical composition process for ASR is described. Some experiments show that care should be taken with silence models.