Semitic languages originally had three grammatical numbers: singular, dual, and plural. Classical Arabic still has a mandatory dual (i.e. it must be used in all circumstances when referring to two entities), marked on nouns, verbs, adjectives and pronouns. Many contemporary dialects of Arabic still have a dual, as in the name for the nation of Bahrain (baħr sea + -ayn two), although it is marked only on nouns. It also occurs in Hebrew in a few nouns (šana means one year, šnatayim means two years, and šanim means years), but for those it is obligatory. The curious phenomenon of broken plurals - e.g. in Arabic, sadd one dam vs. sudūd dams - found most profusely in the languages of Arabia and Ethiopia, may be partly of proto-Semitic origin, and partly elaborated from simpler origins.