The use of the apostrophe with nouns to show ownership (Saxon Genitive?) has always puzzled me. I haven't been able to find a convincing rule in any of the grammar or usage books where I've checked. Some advise you to avoid using it with things, ideas or animals, whereas some others accept this use.
found the following examples which don't sound right to my non-native
What concerns me most, however, is whether there is a rule which will allow me to generate my own grammatical utterances.
This is a very difficult area to advise on, Arrosane, as it usually boils down to what sounds right is right. All the examples of possessives that you quote are quite plausible and sound quite natural. But I would also agree with the advice 'when in doubt, use the of the construction.'
In general there is some preference for the possessive pattern when
a person, rather than a thing, is being described. Thus, we would
person might be extended to include animals or groups of human
beings, so we would have:
people's names end in 's', you can either add ' or 's
(Charles' or Charles's) and choose pronunciation accordingly,
either /iz/ or /isiz/. You might sometimes need to choose the latter
to make the meaning clear.
For example, if you speak the sentence:
with /isiz/ at the end, it is clear that you are talking about houses in both cases!
I hope that is clear!