Sardinian (sardu, limba sarda, lingua sarda) is a Romance language primarily spoken on three-quarters of the island of Sardinia (Italy). A number of scholars consider it the most conservative Romance language, and its substratum (Paleo-Sardinian or Nuragic) has also been researched. A 1949 study by Italian-American linguist Mario Pei, analyzing the degree of difference from a language's parent (Latin, in the case of Romance languages) by comparing phonology, inflection, syntax, vocabulary, and intonation, indicated the following percentages (the higher the percentage, the greater the distance from Latin): Sardinian 8%, Italian 12%, Spanish 20%, Romanian 23.5%, Occitan 25%, Portuguese 31%, and French 44%.