A processor-enabled navigation device capable of displaying a route and of producing sounds from data, said device having: a processor for processing sounds digitally and means for audible delivery thereof; a memory in which is stored a database of a plurality data at least some of which is in the form of text-based indicators, and one or more pre-recorded sounds; data transfer means by which the data is transferred between the processor of the device and said memory; operating system software, or a program executing thereon, which controls the processing and flow of data between the processor and the memory, and whether said sounds are audibly reproduced by repeatedly determining one or more physical conditions which are compared with one or more reference values provided in the memory such that the satisfaction of the condition gives rise to an event requiring a sound to be produced by the device by: one or more pre-recorded sounds stored on the device; a sound digitally rendered by a text-to-speech component provided in the device and with which the operating system software or the program executing thereon interacts by providing thereto a text-based indicator retrieved from the database and appropriate for the event; or a combination of the above, characterised in that: the device further includes graphical user interface means, and the operating system software, or the program executing thereon, causes the display of one or more option selection pages on the graphical user interface means including selectable options to digitally render sound by means of the TTS component for one or more different event types requiring audible notification to the user and/or recall one or more of the pre-recorded sounds to notify such events, and is arranged to receive a user input selecting one or more of the selectable options, wherein a warning is issued to said user that certain events may not be audibly identified when a selection is made for exclusive use of pre-recorded sounds. a processor for processing sounds digitally and means for audible delivery thereof; a memory in which is stored a database of a plurality data at least some of which is in the form of text-based indicators, and one or more pre-recorded sounds; data transfer means by which the data is transferred between the processor of the device and said memory; operating system software, or a program executing thereon, which controls the processing and flow of data between the processor and the memory, and whether said sounds are audibly reproduced by repeatedly determining one or more physical conditions which are compared with one or more reference values provided in the memory such that the satisfaction of the condition gives rise to an event requiring a sound to be produced by the device by: one or more pre-recorded sounds stored on the device; a sound digitally rendered by a text-to-speech component provided in the device and with which the operating system software or the program executing thereon interacts by providing thereto a text-based indicator retrieved from the database and appropriate for the event; or a combination of the above, characterised in that: the device further includes graphical user interface means, and the operating system software, or the program executing thereon, causes the display of one or more option selection pages on the graphical user interface means including selectable options to digitally render sound by means of the TTS component for one or more different event types requiring audible notification to the user and/or recall one or more of the pre-recorded sounds to notify such events, and is arranged to receive a user input selecting one or more of the selectable options, wherein a warning is issued to said user that certain events may not be audibly identified when a selection is made for exclusive use of pre-recorded sounds. the device further includes graphical user interface means, and the operating system software, or the program executing thereon, causes the display of one or more option selection pages on the graphical user interface means including selectable options to digitally render sound by means of the TTS component for one or more different event types requiring audible notification to the user and/or recall one or more of the pre-recorded sounds to notify such events, and is arranged to receive a user input selecting one or more of the selectable options, wherein a warning is issued to said user that certain events may not be audibly identified when a selection is made for exclusive use of pre-recorded sounds.