I read the following in the "English Grammar in use" book:
- You can’t blame me for what happened to you. It was your own fault.
- You have to make your own decisions. I can’t tell you what to do.
Can we omit “own” from these sentences?
Is it grammaticality correct?
Does the meaning change?
There is the context in relation to the word "own" that needs to be considered (even if unknown): the subject, other surrounding sentences, and the specifics of the situation.
Example where the meaning is different:
Situation: A food fight occurs, person "A" walks into it, and joins in. Everyone is disciplined, except the authority and person "B" (the "blamer" whom wasn't present).
- You can’t blame me for what happened to you. It was **your own** fault.
The sentence "it was your own fault" suggests that it was person A's fault for getting involved, not running fast enough or disguising their actions, or not explaining their way out of it.
It is not the fault of person B, only person A; that they got in trouble. Not the fault of the others involved either.
- You can’t blame me for what happened to you. It was **your** fault.
This enforces the fault upon person A by exaggerating and placing the entirety of the blame on them. It suggests that: It is person A's fault that the food fight started (possible), it is their fault for joining in (certainty), it was their fault that an authority figure showed up (possible), it was their fault that the authority figure didn't support the action (unlikely) and finally their fault they got in trouble (true), and not person B's (maybe, did they start the fight and leave, call the authority figure?).
I'll keep the second example much shorter.
- You have to make **your own** decisions. I can’t tell you what to do.
Suggests that advice is often asked for and the person being asked has tired of trying to assist. Please don't ask more about this and ask much less frequently (if at all) in future.
- You have to make **your** decisions. I can’t tell you what to do.
Suggests that it's a singular situation: "Should I go to work, or to school?".
There's more than a single decision to be made, to decide this one question. The person being asked doesn't feel capable (or does not want to) of assisting with this particular problem. If something else comes up, feel free to ask.
Those are not exhaustive examples, just to show that exact usage can be tricky and exactness usually requires complete knowledge and analysis - most people aren't precise and if you're learning English many people understand to allow some flexibility in interpreting the meaning.
As you (well, some people) can see in the second two examples there might be some flexibility, or professed importance, to still continue to ask for help and seek an exception to the request/weak (polite) demand.