A handheld electronic device includes a reduced QWERTY keyboard and is enabled with disambiguation software and prediction software. In response to an ambiguous input, the system provides one or more disambiguated interpretations of the ambiguous input. In some circumstances, the system can additionally provide one or more completions, i.e., predictions of future characters. However, in other circumstances the outputting of completions of an ambiguous input can be suppressed in order to avoid distracting the user and to provide more meaningful results to the user.