As far as I understand, he doesn't have the power to say one way or another. Technically his license lets him define anything he wants to about tlhIngan Hol.
Strictly speaking, he doesn't even have this power. Paramount is the real owner of the license to
tlhIngan Hol.
Whatever 'power' Okrand has technically derives from the fact that so far he's the only person who's been
permitted to produce licensed product for Paramount, at least to the level of detail of the Klingon Dictionary.
My own circle of
tlhIngan Hol speakers has decided to adopt Okrand as the only source of legitimate
canon mainly for pragmatic reasons.
Arguably anything he says about Klingon culture, behaviour, biology, oreinteering/navigation or anything else is not canon. Only the acutaul vocabulary, grammar, morphology, orthography and anything else that describes the language is canon. Anything he describes about how the language is used or the people that use the language should probably be treated as non-canon speculation.
Probably true, but there is some overlap, as when he tries to explain an unfamilliar word by describing the
cultural context it's used in.
To my knowledge Paramount has enforced this destinction only once, noting that anything Okrand has said about "Maltz" is not canon, going so far to say that Maltz did not turn and is not serving Okarnd as a lingusistic informant.
This I have not heard...
Given that most everything Okrand has presented have reportedly come from "Maltz"... There is some reason to doubt anything he's ever said...
As I said, my own circle of
tlhIngan Hol speakers (mostly the Klingon Language Institute - I am beginning
to realize there are many other 'schools' of opinion besides this one!) decided long ago to adopt Okrand as
our only source of canon. We did this purely for pragmatic reasons, to keep
tlhIngan Hol from
devolving into a myriad of mutually unintelligible dialects. Unlike natural-language communities, our
community is small, geographically scattered, and lacking a pool of native language speakers to be
the final judges of 'correct usage'. If the goal was to have a world-wide (!) language that would
be mutually understandable by everyone who used it, it always seemed logical to me to set a
standard, and it seemed logical that the standard would be the language's creator, Marc Okrand.
(Paramount's various independent offerings in the form of phrases in the TV shows or games we
dismissed because they couldn't be understood in the context of the 'standard' Okrandian
language - maybe they're dialects.).
-- ter'eS