Tūtū can be used for both male and female grandparents. To make it more gender specific add kāne for male and wahine for female. Tūtū kāne = grandpa Tūtū wahine = grandma Kupuna kāne = grandfather Kupuna wahine = grandmother Kūpuna kāne = grandfathers (plural, more than 1, not possessive as in my grandfather's watch) Kūpuna wahine = grandmothers (plural meaning more than 1 grandmother, or someone like an grand aunt of that generation) 'Elemakule = old man Luahine = old woman
I don't think it differs by island. I was taught like English "w" after "o" and "u." Like Hawaiian v-sound after "i" and "e." Optional after "a" or initial, so "Hawa(i)'i" and "Hava(i)'i" both (or all four) OK, and either "waikīkī" or "vaikīkī". But I have never heard "pu'uwai" for "heart," always "pu'uvai," in spite of the "u" in front of it. Maybe "water" is never "wai," and that's why?
I believe that a comma would come after kela and before tūtū wahine to read as: Who is that, grandma? It might mKe kt clearer, but i m not sure they have punctuations except for voice inflection. As for the discussion on the rules for w sounds. I was taught if its at tbe beginning of a word or name it a -W-(wuh) sound. If its between two vowels its a -V- sounding w. Ergo Hawai'i is v Ha-vai-ee. Waikiki and Waianae, Waipahu, all have wuh sounds.