Thanks for the quick reply.
I tried the GoldWave editor but what I have found was 2 channels (left and right) which are identical. Their graphs are the same and when I chose left channel I heard both languages and the same happened when I chose the right channel.
According to your experience, is there hope to separate the 2 streams to 2 different languages?
the codec of the audio stream is ID'd as MPEG-1 Layer 3, if it helps in any way.
Again, thanks for all the efforts.