you can only have 3 differents dictionnaries
they can only be suplied by nokia, you cannot use your own.
I suspect that ther is not a great variety of language (that I cannot chek for the moment). For exemple,
With my old N95 and mobipocket I regullary used thoses dictionnaries :
french Vietnamese / vietnamese french
harrap's english french / harrap's french english
french / french definitions
french / french encarta encyclopedia
and more ...