Hello Jay and Tom
The USA and UK are two countries separated by one language - English -
and the ne'er the twain shall meet ;-())))
Avoiding the use of the apostrophe is one thing we should consider. It does help users whose mother tongue is not English because the grammar rules for the apostrophe are difficult to understand with the possessive apostrophe being the hardest. Comes from personal experience of working in several non-English countries. Also, if you work in the aviation industry and use Simplified English, the apostrophe is definitely out.
I think the native English speakers should remember to avoid contractions and other be more precise about possessives.
Also, it does not help that there are two major spelling systems in English, fortunately the differences are generally very consistent (*our vs *or or *er vs *re in word endings).
Another problem is that UK, Canadian, US, etc. local idioms are sometimes incomprehensible to other. And some words are have some what different meanings in US English than UK English. (the boot of a car (UK) is the trunk of a car (US)) Wikipedia has several lists of these differences and some can be very humorous.