Esperanto vocabulary and grammatical forms derive primarily from the Romance languages, with substantial contributions from Germanic languages. The language occupies a middle ground between "naturalistic" constructed languages such as Interlingua, which borrow words en masse from their source languages with little internal derivation, and a priori conlangs such as Solresol, in which the words have no historical connection to other languages. In Esperanto, root words are borrowed and retain much of the form of their source language, whether the phonetic form (eks- from international ex-, vualo from French voile) or orthographic form (teamo and boato from English team and boat, soifo from French soif). However, each root can then form dozens of derivations which may bear little resemblance to equivalent words in the source languages, such as registaro (government), which is derived from the Latinate root reg (to rule) but has a morphology closer to German or Russian. Source languages Zamenhof took most of his Esperanto root words from languages of the Italic and Germanic families, principally Italian, French, German, Yiddish, and English. A large number are what might be called common European international vocabulary, or generic Romance: Roots common to several languages, such as vir- "man", found in English words such as virile, and okul- "eye", found in oculist. Some appear to be compromises between the primary languages, such as tondri (to thunder), per French tonner, Italian tuonare, German donnern, and English thunder. Romance and Germanic The main languages contributing to Zamenhof's original vocabulary were French, English, and German, the modern languages most widely learned in schools around the world at the time Esperanto was devised. The result was that about two-thirds of this original vocabulary is Romance, and about one-third Germanic, including a pair of roots from Swedish: Swedish: Comparative the (as in "the more the merrier") ju ... des. A couple of words, strato (street) and gisto (yeast), are closer to Dutch (straat, gist) than German (Straße [ʃtrasə], Gest), but this may be a compromise between German and English the way ŝtono (stone) is a compromise between German Stein [ʃtajn] and English. (There's also ronki (to snore), Dutch ronken.) Fajro (fire) matches the pronunciation of English fire, but is also spelled and pronounced as Yiddish פֿײַר fajr. Indeed, much of the supposedly German vocabulary actually appears to be Yiddish, specifically Zamenhof's native Bialystok (Northeastern) dialect, which had formed the basis of his abortive attempt to standardize that