Re: Why don't you learn English?
Who knows English, who only English knows?
Some languages are more flexible than others, and in some adjectives, nouns and verbs are interchangeable. In Dutch and German I could easily use HTML5 as a verb, and in context it would even make sense. For example: "we're currently HTML5-ing our Webinterface."
That said, I can see what an HTML5 experience is. You /can/ use HTML5 as an adjective. Perhaps this strokes against the 'Current Best Practices of English Language Usage' but it certainly does not disagree with semantic rules of other languages.
So it is possible to deliver an HTML5 experience. And, when the look and feel of a website is akin to a local app, one might even say, indeed, a native HTML5 experience.
Please note however, that the keyword here is 'experience'; a clever marketing word that has nothing to do with any technology involved. It is subjective, unmeasurable and only vaguely defined in terms of look&feel (which in turn is also subjective and unmeasurable). And you can claim exclusivity on a certain kind of experience, simply by changing the definition.
So, there you have it. IE can deliver a native HTML5 experience, at least from an end user perspective. Programmers, developers, administrators et al might get confused by using otherwise well defined jargon in such a marketing manner. But that is sales people for you*). They will gladly tie some buzzwords together with vague concepts to form sentences that reveal nothing to the initiated.
*) If you like this sort of thing, we at work call our serverpark 'the fat clients' we call the patch panels 'the servers', we call desktops 'thin clients' and we call the databases 'the intranet' ... all according to real life misuse of IT jargon by sales people and consultants.