I am surprised to find "-oog" is the official pronunciation as terminal "-gh" is pronounced differently than "-g" in English; I was expecting answers ending in "-f" or "-h" sounds or maybe "-k". I guess I should expect weird spellings from the realm that brought us Dr'izz't Do'Urde'n'''.
I have to add hyphens between the syllables in all the Kuo-Toa words in order to be able to say them (or even read them in my head). Even then, I usually just say the first syllable and let the rest trail off as a blub-blub-gurgle-gurgle mutter. Which actually works well.