In linguistics, the Philippine languages are a 1991 proposal by Robert Blust that all the languages of the Philippines and northern Sulawesi—except Sama–Bajaw (languages of the "Sea Gypsies") and a few languages of Palawan—form a subfamily of Austronesian languages. Although the Philippines is near the center of Austronesian expansion from Formosa, there is little linguistic diversity among the approximately 150 Philippine languages, suggesting that earlier diversity has been erased by the spread of the ancestor of the modern Philippine languages. Philippine languages make up the oldest non-Formosan languages of the Austronesian language family, with several languages preserving the proto-Austronesian schwa and d–r assonance lost in the Sunda–Sulawesi languages.