Abstract: A character selection keyboard for use in connection with an ideographic language of which the characters can each comprise one or more of a set of character components, as defined. The keyboard comprises an array of character component keys each bearing a symbol corresponding to a character component. Some of the components have separate linguistic identity and can accordingly be used in isolation to constitute characters in the ideographic language; these components are all depicted within a part of the array which is visually distinct from the rest of the keyboard. The keyboard can be connected in a composing system in which data defining the structure of the characters constituted by the components selected by key actuation is derived from a programmable store in response to key signals generated by the key actuation. The keyboard may also be used in typewriters, telex machines, and other systems requiring data input.