Because i have no idea whats the content of the rom but i expected some kind of wave data i started with importing the .bin file i have read from the rom into Audacity.

First i had no luck with that but i kept going with different import settings until i started to hear something that really sounded like a voice. The quality is really bad and you can barely make out the words. But at least now i know that there is real voice data on this chip.

These are the settings i used in Audacity:

Here is a small section of the badly decoded voice. It says "Tür hinten rechts, nicht geschlossen, Tür vorne rechts" and then it plays the two sounds that it can make (A rising 2 tone sound and a falling 3 tone sound).

https://cdn.hackaday.io/files/1920428216324928/SYPx54GerTEST.mp3

Thats another huge success.

I looked at the waveform and noticed interesting details. There are sections that do not make sound... Thats probably data. Each sound is divided from the next with an interesting squiggly line.

And now the crazy thing... There is a second language... I think its Italian. The second half of the ROM is entirely in italian.

https://cdn.hackaday.io/files/1920428216324928/italian_syp_test1.mp3

The italian part is exactly made like the german part. First some kind of data, followed by the voice sample. Also all samples are divided by a squiggly line.

You can really see that the wave data is converted wrong. It looks like the waves come from the bottom and are clipping all the time.

I have marked one of the dividers between the samples. they should be easy to find in the binary data.

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The 2 data blocks are divided by this gap shown below. I have highlighted the gap and the data in front of the voice samples up to the first squiggly line. The "Data Data" clearly looks different from the voice Data.

IF YOU HAVE AN IDEA HOW TO DECODE THIS KIND OF RAW AUDIO please let me know... I have no idea how PCM and Waves work... 

The next step is to dive deeper into the raw hex bytes of the BIN file. With the infos we discovered here it should be easy to find these blocks of audio and data.