9. The method of claim 1 , comprising: translating said at least one keyword into at least one pattern by means of the pattern dictionary; feeding said at least one pattern as an input pattern into said trained second neural network; obtaining at least one output pattern from said trained second neural network; and translating said at least output pattern into at least one keyword by means of the pattern dictionary.
9. The method of claim 1 , comprising: translating said at least one keyword into at least one pattern by means of the pattern dictionary; feeding said at least one pattern as an input pattern into said trained second neural network; obtaining at least one output pattern from said trained second neural network; and translating said at least output pattern into at least one keyword by means of the pattern dictionary. 10. The method of claim 9 , wherein the second neural network is hierarchical, said at least one input pattern is fed into at least one lower layer of the hierarchy and said at least one output pattern is obtained from at least one higher layer of the hierarchy.