There are people with no internal monolog, for example. They don't "talk" internally.
Another example is that while I "see" things easily, they are very abstract. It doesn't relate to world world things, but they can create intuitive connections. I can't really think that well without "day dreaming" and staring off into the distance.
However I can't really "hear" things internally. Sometimes, rarely, I can listen to music in my brain as if I am hearing it, but it's a fluke. It is extremely unusual.
Were as I have had musician friends that can record and playback every note internally. I remember back in the day when Little Caesars had "Simon Says" style musical game were you could win a free pizza... the owner of the store would get so angry at my friend for effortlessly beating it that he would just hand him a free pizza and tell him to leave every time we would show up with a handful of quarters. He would have to lose on purpose so we could win just a free soda to go along with the free pizzas.
My girlfriend, when she hears a catchy song, can have it playing so loudly in her head that it will keep her up at night. It is not something she has lot of control over. I am banned from playing certain songs around her because it will fuck up her sleep schedule. It is not even related to whether she likes the song or not.
According to her the most evil song that ever created is 4 Non Blondes' "What's Up".
I think the idea that "we need to be cautious" in regards to the article is missing the point. It's not trying to claim that "If you get head injury everything will be alright".
I think the main point is something more along the lines of:
We don't know how the brain works. When people talk about "language centers" and this part of the brain does that... They are factually wrong. They don't know that.
They know that MRIs can show different parts of the brain getting more or less blood flow when people see different things or carry out different tasks, and there is some correlation between different types of brain injury and different types of cognitive impairment, but the ultimate meaning behind all that is still largely a mystery.