Listening Part A can be a conversation between any one of the healthcare professionals who can take OET and a patient or relative of the patient.
For example it could be between a physiotherapist and a patient, an optometrist and a patient, even a vet and the owner of a pet.
It’s a good idea to learn vocabulary which is really common to the other OET professions as it is likely to come up in Part A. This vocabulary is also very often common to patients.
For example, for podiatry you could learn the names for different parts of the foot; for dentistry you could learn the different parts of the mouth and teeth etc.
If you know any colleagues or friends in these professions you could ask them for their most frequently used words. Alternatively, do some research online for “common ______ words” (replacing the ____ with the name of the profession)
Finally, if you still need a bit more persuasion, learning around 10 words for the 12 professions is not going to be a waste of time. After all, every one of us is likely to need care from these professionals at some point in our lives.