An Adelaide mother has pleaded for a thief to return a device which helps her daughter, who has cerebral palsy, to speak using eye movements.

Key points: Natalie Armitstead's daughter Jessica uses an eye-tracking device to be able to speak

Natalie Armitstead's daughter Jessica uses an eye-tracking device to be able to speak It was stolen from her unlocked car on Saturday night

It was stolen from her unlocked car on Saturday night She wants the thief to return it

The $25,000 Tobii Eye Gaze computer was stolen from Natalie Armitstead's unlocked car parked on the Esplanade in Largs Bay on Saturday night.

Her 13-year-old daughter Jessica has cerebral palsy and is non-verbal.

The device allows Jessica to speak by looking at different words, icons and numbers on a screen attached to her wheelchair.

It then reads what she wants to say out loud.

"Unfortunately, that was in the car on Saturday night and that is what was taken," Ms Armitstead told ABC Radio Adelaide.

The device looks like a laptop and is customised for Jessica's needs, with pictures of her family and animals on it.

"Basically anyone who is non-verbal can use it, however each device has standard icons on it and then it has these special things like it has photos of all her family on it, photos of where she likes to go, books she likes to read, animals photos on it," Ms Armitstead said.

Jessica's school, Adelaide West Special Education Centre, has loaned her another eye-tracking speaking device until hers is recovered.

"The beauty of a child having a device like this is if she's down the street and someone says 'hi' to her she can communicate back," Ms Armitstead said.

"Without this, she can just look at them and smile."

Jessica Armitstead, 13, using the Tobii Eye Gaze computer that was stolen from her mother's car. ( Supplied )

Thief urged to return device

Ms Armitstead wants the burglar to return the device "no questions asked".

The cafe owner said her daughter gave her the "stink eye" all Sunday after the theft.

"It's really of no use to anybody else — that's basically it," she said.

"They possibly thought they were taking a computer or a laptop; they were, but not a usable one."

SA Police said the theft happened some time between 10:30pm on Saturday and 6:45am on Sunday.

"Anyone who saw or heard any suspicious activity in the area or who has any information on the whereabouts of the special needs device is urged to contact Crime Stoppers on 1800 333 000 — you can remain anonymous," police said in a statement.