A language input architecture receives input text (e.g., phonetic text of a character-based language) entered by a user from an input device (e.g., keyboard, voice recognition). The input text is converted to an output text (e.g., written language text of a character-based language). The language input architecture has a user interface that displays the output text and unconverted input text in line with one another. As the input text is converted, it is replaced in the UI with the converted output text. In addition to this in-line input feature, the UI enables in-place editing or error correction without requiring the user to switch modes from an entry mode to an edit mode. To assist with this in-place editing, the UI presents pop-up windows containing the phonetic text from which the output text was converted as well as first and second candidate lists that contain small and large sets of alternative candidates that might be used to replace the current output text. The language input user interface also allows a user to enter a mixed text of different languages.