To provide an input system with operability that has almost no difference between a general personal computer and this in terms of Spanish portable input terminal.

In an input keyboard with three rows and five columns, a plurality of consonants and a plurality of vowels are assigned to some of its keys, thereby systematically sorting all alphabets into a consonant keyboard and a vowel keyboard. In addition to five basic vowels, ten pairs of double vowels with high use frequency of spelling are assigned to the vowel keyboard. An input system for automatically alternating the two keyboard according to input is employed. The consonants and vowels are simultaneously input by depressing corresponding keys one time. An input result is compared with a prepared database for making a determination. Thereby, a system for automatic alteration as a whole is achieved and a similar content is input with key depressions fewer than the conventional key depressions.