1. A game apparatus in which a scenario proceeds in such a way that a player character is moved on a field produced in a three-dimensional virtual space in a memory through a controller so as to search and obtain items located on the field, comprising: a sentence item control table stored in the memory of the game apparatus, said sentence item control table storing a first set of information associated with a plurality of sentence items, the first set of information comprising: a kind of language set for each sentence item, a display position on the field for each sentence item, and game information text for each sentence item; an item disclosure object table stored in the memory of the game apparatus, said item disclosure object table storing a second set of information associated with a plurality of item disclosure objections, the second set of information comprising: a disclosure item associated with each item disclosure object, a kind of language and a language level set for each item disclosure object, and a display position on the field for each item disclosure object located on the field; a language skill table (TB 2 ) stored in the memory of the game apparatus, the language skill table storing a language skill level of the player character for each kind of language identified in the sentence item control table and the item disclosure object table; and at least one processor, coupled to the memory and configured to: access the sentence item control table and the item disclosure object table, and further configured to control a language skill level of the player character for each kind of language identified in the sentence item control table and the item disclosure object table; locate two or more sentence items at predetermined positions on the field based on the display position on the field of each sentence item stored in the sentence item control table; locate two or more item disclosure objects on the field; wherein a kind of language and game information text are set for each of the two or more sentence items; wherein a disclosure item, the kind of language and a language level are set for each of the two or more item disclosure objects; in response to one or more instructions from a player through the controller cause the player character to access a sentence item located on the field and to read the game information text of the sentence item by referring to the sentence item control table; wherein whenever the player character reads the game information text of the sentence item, execute a process of improving the language skill so as to store an updated skill level of the player character in the language skill table for the kind of language set for the sentence item accessed by the player character and stored in the sentence item control table; judge the kind of language and the language level associated with the item disclosure object accessed by the player character by referring to the item disclosure object table and referring to the skill level of the player character for the kind of language associated with the item disclosure object requested to be accessed by referring to the language skill table, and comparing the skill level and the language level set for the accessed item disclosure object, only when the skill level of the player character is the same as the language level set on the item disclosure object or higher, grant access to the item disclosure object requested to be accessed; and execute a process of developing and displaying the disclosure item associated with the item disclosure object on the field by referring to the item disclosure object table when the execution of the process of accessing the item disclosure object is enabled by the at least one processor.