Hi Stefan, I have a strange problem with composition with the fsa tool - It says that " 'some word' is not in second alphabet". What does it mean? Could you please have a look at the files that I'm trying to compose - a dictionary transducer and a language model transducer. I've also attached the error log. The command I use is fsa att:Dict_2003+.extended.fsm.txt att:lm.txt compose write att:LoG.txt Thanx in advance, Emilian P.S. What is "the second alphabet" anyway? The output or the input alphabet of the second transducer?