A method of disambiguating a character input into a handheld electronic device, the handheld electronic device including an input apparatus for inputting characters into the device, an output apparatus for outputting characters, and a processor apparatus for electronically processing characters, including a memory having a plurality of objects stored therein, the plurality of objects including a plurality of language objects that may be constructed or identified from one or more linguistic characters to generate text, each of at least some of the language objects comprising a first linguistic character, the input apparatus including a plurality of input members (28,34), each having a plurality of linguistic characters assigned thereto, the method comprising the steps of: detecting an ambiguous input including a number of input member actuations of a number of the input members, wherein the ambiguous input has an input case makeup of an input sequence of upper and lower case linguistic characters; generating a plurality of prefix objects, each prefix object comprising a permutation of linguistic characters corresponding with the ambiguous input; for a first prefix object, identifying first and second language objects corresponding with the first prefix object, at least a portion of the first language object having a first case makeup of a first sequence of upper and/or lower case linguistic characters, at least a portion of the second language object having a second case makeup of a second sequence of upper and/or lower case linguistic characters, the second case makeup being different to the first case makeup; determining that a portion of the input case makeup corresponds with at least a portion of one of the first case makeup and the second case makeup, and that said portion of the input case makeup includes an upper case linguistic character that corresponds to a same upper case linguistic character within said at least a portion of the one of the first case makeup and the second case makeup; determining that another portion of the input case makeup includes a linguistic character that is lower case, and that a corresponding linguistic character of the one of the first case makeup and the second case makeup is a linguistic character that is upper case; outputting as a relatively more preferred variant, in a predetermined quantity of alternative proposed interpretations of the ambiguous input, the first prefix object in accordance with the one of the first case makeup and the second case makeup; and outputting as a relatively less preferred variant the first prefix object in accordance with the other of the first case makeup and the second case makeup. detecting an ambiguous input including a number of input member actuations of a number of the input members, wherein the ambiguous input has an input case makeup of an input sequence of upper and lower case linguistic characters; generating a plurality of prefix objects, each prefix object comprising a permutation of linguistic characters corresponding with the ambiguous input; for a first prefix object, identifying first and second language objects corresponding with the first prefix object, at least a portion of the first language object having a first case makeup of a first sequence of upper and/or lower case linguistic characters, at least a portion of the second language object having a second case makeup of a second sequence of upper and/or lower case linguistic characters, the second case makeup being different to the first case makeup; determining that a portion of the input case makeup corresponds with at least a portion of one of the first case makeup and the second case makeup, and that said portion of the input case makeup includes an upper case linguistic character that corresponds to a same upper case linguistic character within said at least a portion of the one of the first case makeup and the second case makeup; determining that another portion of the input case makeup includes a linguistic character that is lower case, and that a corresponding linguistic character of the one of the first case makeup and the second case makeup is a linguistic character that is upper case; outputting as a relatively more preferred variant, in a predetermined quantity of alternative proposed interpretations of the ambiguous input, the first prefix object in accordance with the one of the first case makeup and the second case makeup; and outputting as a relatively less preferred variant the first prefix object in accordance with the other of the first case makeup and the second case makeup.