First of all you should get the latest dhvani source code from CVS in sourceforge. Compile it and install.
To create an audiobook follow these steps
You need the text in utf-8 format. No need to specify the langauge. Dhvani will detect the langauge automatically.
dhvani -o audiobook.wav textfile<br />
oggenc -B 16 -C 1 -R 16000 audiobook.wav<br />
Now you have a file called audiobook.ogg. If you prefer ogg, then your audiobook is ready. If you want the file in mp3 format
(This will create a file named audiobook.ogg.wav )
lame --preset 192 -ms -h audiobook.ogg.wav
(install lame if it is not present using your package manager)
Now your mp3 file is ready. Transfer it to your music player and enjoy!
I have a sample Malayalam Audio book here
Note: The speech produced for Languages other than Hindi and Malayalam may not be as per their pronunciation rules. There are two solution for this:
a) Teach me that langauge 😉 or
b) Submit a patch to fix that language module
You can find the Dhvani documentation here