Information display apparatus and information display method

An information display apparatus, comprising:

• an information display part, which displays various information;
• a communication part, which performs one of wireless communication and wired communication to or from a portable terminal device, wherein the information display part:
• stores information pertaining to display priorities that are assigned to different items including different telephone communication states and different screen categories of a navigation apparatus;
• displays a first screen that notifies a user that electronic mail has been received when the portable terminal device has received the electronic mail;
• and
• continues to display a second screen that notifies a user of at least a given screen category of the navigation apparatus when the portable terminal device has received the electronic mail while the second screen is displayed,
• an operation reception part, which receives a user's operation;
• a voice information generation part, which generates voice information from text of the electronic mail received by the portable terminal device;
• and
• a voice output part, which outputs to a speaker the voice information generated by the voice information generation part when the operation reception part receives a predetermined operation, wherein
• some telephone communication states and some screen categories of the navigation apparatus are assigned a higher display priority than a display priority of the first screen, such that when the electronic mail is received, while the display is displaying the second screen associated with a higher display priority item, the display continues to display the second screen until after display of the second screen is finished, at which point the display begins to display the first screen,
• some telephone communication states and some screen categories of the navigation apparatus are assigned a lower display priority than the display priority of the first screen, such that when the electronic mail is received, while the display is displaying the second screen associated with a lower display priority item, the display immediately stops displaying the second screen and is switched to the first screen, such that whether display of the second screen information is changed or maintained depends on the telephone communication state or the given screen category of the navigation apparatus,
• the display of the first screen is prevented until after a hands-free telephone communication is completed, and
• on the first screen, a read out instruction of the text of the electronic mail is received from the user.