Issaouane Erg confined to basins. Sand in the Issaouane Erg, below the level of the sand dunes, has accumulated to a depth of 20 to 30 meters. It has barchan dunes as well as star dunes of 300 to 430 meters high. The presence of both barchan dunes (which form due to unidirectional winds) and star dunes (which form when winds from various directions deposit sand) "suggests that wind regimes have changed over time". NASA's "Earth Observatory" notes all three types of erg dunes are present in the photos of the Issaouane Erg taken from the International Space Station: stationary mega dunes,
Varieties of Arabic French in Lebanon, and English and Hebrew in Israel. However, a much more significant factor for all five dialect groups is, as Latin among Romance languages, retention (or change of meaning) of the form of Classical Arabic used in the Quran. The following example illustrates similarities and differences between the literary, standardized varieties, and major urban dialects of Arabic. Maltese, a distantly related Siculo-Arabic language descended from Maghrebi Arabic is also provided. "True pronunciations differ; transliterations used approach an approximate demonstration. Also, the pronunciation of Modern Standard Arabic differs significantly from region to region." For the sake of comparison, consider