1. A Hangeul input keypad comprising: a plurality of consonant keys to which at least two basic consonants selected from the group consisting of , , , , , , , and are assigned; a plurality of vowel keys to which at least one basic vowel selected from the group consisting of , , , , , , , , and is assigned; and a shift key for converting the basic consonants to extended consonants selected from the group consisting of , , , , , , , , and , wherein the basic consonants convertible to the extended consonants by the shift key (hereinafter “basic convertible consonants”), which are , , , , and , are assigned to consonant keys (hereinafter “basic convertible consonants keys”) located adjacent to the shift key, all of the consonant keys are disposed adjacent to each other and all of the vowel keys are disposed adjacent to each other such that a consonant key group including all of the consonant keys is separated from a vowel key group including all of the vowel keys on a keypad, the number of the consonant keys is less than that of the vowel keys, and the shift key is surrounded by the basic convertible consonant keys, and the shift key is not used for converting the basic vowels.
1. A Hangeul input keypad comprising: a plurality of consonant keys to which at least two basic consonants selected from the group consisting of , , , , , , , and are assigned; a plurality of vowel keys to which at least one basic vowel selected from the group consisting of , , , , , , , , and is assigned; and a shift key for converting the basic consonants to extended consonants selected from the group consisting of , , , , , , , , and , wherein the basic consonants convertible to the extended consonants by the shift key (hereinafter “basic convertible consonants”), which are , , , , and , are assigned to consonant keys (hereinafter “basic convertible consonants keys”) located adjacent to the shift key, all of the consonant keys are disposed adjacent to each other and all of the vowel keys are disposed adjacent to each other such that a consonant key group including all of the consonant keys is separated from a vowel key group including all of the vowel keys on a keypad, the number of the consonant keys is less than that of the vowel keys, and the shift key is surrounded by the basic convertible consonant keys, and the shift key is not used for converting the basic vowels. 17. A Hangeul input method using the keypad of claim 1 , wherein: input of a basic consonant is performed by selecting a consonant key to which the basic consonant to be input is assigned, and selecting the basic consonant to be input by operating the selected consonant key; input of an extended consonant is performed by selecting a basic convertible consonant key to which the basic convertible consonant corresponding to the extended consonant to be input is assigned, and selecting the extended consonant to be input by repeatedly operating the selected basic convertible consonant key; input of a basic vowel is performed by selecting a vowel key to which the basic vowel to be input is assigned, and selecting the basic vowel to be input by operating the selected vowel key; and input of a combined vowel formed by combining more than two basic vowels is performed by selecting a vowel key to which a first basic vowel (the preceding basic vowel of the basic vowels forming a combined vowel in the writing sequence of the combined vowel in Hangeul) to be input is assigned, and selecting the combined vowel to be input by repeatedly operating the selected vowel key.