-
The shows blatantly violate the phonetic constraints of the language. For example, "Worf" is not a valid Klingon syllable because there's no f sound or letter in Klingon.
-
Pronunciation within the shows is massively inconsistent. For example, people say "gagh" like /gak/, /gaɣ/, /gax/, /gakx/, /gaχ/, /gaqχ/, /gakʼ/, /gaʁ/, and /gaħ/.
-
The phonological inventory, which is supposed to be "alien", is pretty clearly inspired by indigenous languages of the North American Pacific Northwest, and is honestly less strange than some real human languages like Ubykh or !Xóõ.