Although many languages are named for their country of origin, (even if, like English, they can be seen as a 'mashup' of other languages), they are only ever truly 'owned' by those who use them, regardless of their location or background/culture.
As to the nature of the language itself, I have some information to add, though it may not be currently accepted, perceived or understood in such a manner.
What makes the English language what it is, or what it has been able to become, (the good, the bad and the ugly - including all of it's variants), is that it is built upon a very basic philosophy, leading to one basic rule, above and beyond the actual sounds, (and associated symbols) it uses:
WHAT (information) it represents (or words represent), determines and defines HOW it is used (or how they are used).
(Unfortunately, the reverse of that (which is used to study the language, after it has already been used), is currently institutionalised for the teaching and understanding of the language instead - which is leading to a number of issues, though that probably needs a thread of its own.)
What does this mean?
It means that the individual words don't really matter, so long as they fit within the system of basic grammar, and so their context then matters for what they will be perceived as representing.
This is why so many different words can be added to the language so easily, just so long as they're used in a consistent manner for the type of concept they represent. It is also why some forms of slang (rhyming etc.) are not just easy to add, but also tend to be consistent with grammar too.
(Unfortunately, at this time, we don't fully recognise or understand all the concepts the language is used to represent, nor do we describe them in a fully consistent manner, either - (again, mainly due to the wrong philosophy/rule above).)
One of the effects, and benefits, of the (correct) rule, however, is that the same word can be used in different ways, as representing different concepts, that can be easily seen, recognised and understood to be related, since it's the same word, or similar. This again, makes the language easier to learn and expand.
(E.g. a hammer (thing - (noun)), and I hammer (behaviour (verb))).
So this is the nature of the English language - a language with a very basic and simple foundation, that is flexible and powerful enough to be added to by any number of words that we can represent with the symbols we use, just so long as they ultimately obey the basic rule, (and its logical extrapolation within the basic rules of (English) grammar - even if they're not fully recognised atm.).
And that is one of the reasons why it's used as widely as it is, without any real 'problems' (per se).