Some of all of the differences that fall outside of how Morskan is described in KGT could be limited to specific words, as opposed to being broader patterns. But if we are to assume that the ST VI dialect and perhaps even the PK dialect is Morskan, do we have any other information to explain these additional differences from Standard Klingon that aren’t described in KGT? Is there any description or example of the Morskan dialect outside of KGT?
Maybe there's more than one Morskan dialect? It's like saying "British English". Which one?
Also, and this is the answer to a different question than you asked, but {tlhatlh} "gladst" is never explicitly labeled a Morskan word in KGT, and yet must be in a closely-related dialect. It would be pronounced {ghlats} in Morskan, which is close enough to "gladst".
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De'vID