When you first switch on your device, you have to answer a few questions to set up the device. When these questions appear in the wrong language, it's best to soft-reset your device.
Devices which are reset by holding the On/Off button:
Press the On/Off button and keep holding it until you hear the TomTom start sound. This takes at least 15 seconds. Also keep holding down the On/Off button if your device switches off or shows the start-up screen.
Devices which are reset using a paper clip or pen:
Press the reset button using a paper clip or something similar for 15 seconds. Then press the On/Off button for at least 5 seconds.