1. A computer-implemented method for generating a parser combination by combining at least two language processing parsers comprising at least one formal language processing parser and one natural language processing parser, the method comprising steps of: obtaining a declarative description including a plurality of grammar descriptions generated based on characteristics of target text; dynamically generating a parser combination to selectively parse parts of target text with different parsers by combining parsers each associated with at least one of the plurality of grammar descriptions, wherein the generating is carried out using (i) at least one grammar description means and (ii) a computer device, wherein the at least one grammar description means is one of: (i) a grammar description type 1 P 1 until P 2 (P 1 U P 2 ) means to parse input character strings by use of a first parser associated with a first grammar description (P 1 ) until finding at least one input character string first acceptable by a second parser associated with a second grammar description (P 2 ) which is parsed by use of the second parser, and (ii) a grammar description type 2 P 1 for P 2 (P 1 F P 2 ) means to parse input character strings in such a manner that a prefix string of input character strings which are acceptable by the second parser associated with the second grammar description (P 2 ), is cut out and stored, the acceptable input character strings are parsed by use of the second parser, and the cut out and stored prefix string is parsed by use of the first parser associated with the first grammar description (P 1 ).