Senggigi's daily language mix is Bahasa Indonesia as the national lingua franca plus the regional Sasak language of Lombok, with pockets of Balinese in coastal communities. Tourism-facing staff at hotels, dive shops, and the Gili boat quays handle English, but using a handful of Indonesian phrases unlocks friendlier prices at warungs, smoother ojek rides along the coastal road, and warmer interactions at Pura Mertelu and other temples nearby.
Sasak is the indigenous tongue of Lombok and you'll hear it in inland markets and Sasak villages, while Bahasa Indonesia dominates signage, Gojek/Grab apps, and tour operator counters. Sasak shares Malay-Indonesian roots but its phonology and vocabulary differ enough that even a few words earn noticeable goodwill; when in doubt, fall back to Bahasa Indonesia, which is understood island-wide.