Diglossia refers to a situation where two linguistic varieties coexist within a given speech community. One variety, labeled the ‘high variety’, is used in formal domains including education, while the other variety, labeled the ‘low variety’, is used principally in instances of informal extemporaneous communication. The domains of use, however, are not strictly separate and especially so with the increase in electronic modes of communication. This results in what has been described as diglossic code-switching, and the gradual encroaching of, in the case under consideration here, vernacular Arabic upon the domains of use of Standard Arabic. While the genetic relationship between the two varieties is central in the definition of a classical diglossic situation as in the case of Arabic, the concept of diglossia has often been extended in the literature to cover situations of a functional distribution between languages that are genetically distant, such as with the situation of Spanish and Guaraní in Paraguay. In North Africa, vernacular Arabic is in a classical diglossic distribution with Standard Arabic, while the Berber languages are often described as existing in a situation of extended diglossia with Arabic. However, distinguishing between diglossia as it exists between the Arabic dialects and Standard Arabic and the situation of bilingualism that involves Arabic, Berber, and European languages provides the best framework for describing the linguistic situation in North Africa. Diglossia is a key element in understanding the mechanisms of the region’s language contact and change as it plays a central role in shaping language attitude, language policy, and language planning.
Since the start of the Islamic conquest of the Maghreb in the 7th century ce, Berber and Arabic have been in continual contact. This has led to large-scale mutual influence. The sociolinguistic setting of this influence is not the same, though; Arabic influence on Berber is found in a situation of language maintenance with widespread bilingualism, while Berber influence on Arabic is no doubt to a large degree due to language shift by Berber speakers to Arabic. Linguistic influence is found on all levels: phonology, morphology, syntax, and lexicon. In those cases where only innovative patterns are shared between the two language groups, it is often difficult to make out where the innovation started; thus the great similarities in syllable structure between Maghrebian Arabic and northern Berber are the result of innovations within both language families, and it is difficult to tell where it started. Morphological influence seems to be mediated exclusively by lexical borrowing. Especially in Berber, this has led to parallel systems in the morphology, where native words always have native morphology, while loans either have nativized morphology or retain Arabic-like patterns. In the lexicon, it is especially Berber that takes over scores of loanwords from Arabic, amounting in one case to over one-third of the basic lexicon as defined by 100-word lists.
As might be expected from the difficulty of traversing it, the Sahara Desert has been a fairly effective barrier to direct contact between its two edges; trans-Saharan language contact is limited to the borrowing of non-core vocabulary, minimal from south to north and mostly mediated by education from north to south. Its own inhabitants, however, are necessarily accustomed to travelling desert spaces, and contact between languages within the Sahara has often accordingly had a much greater impact. Several peripheral Arabic varieties of the Sahara retain morphology as well as vocabulary from the languages spoken by their speakers’ ancestors, in particular Berber in the southwest and Beja in the southeast; the same is true of at least one Saharan Hausa variety. The Berber languages of the northern Sahara have in turn been deeply affected by centuries of bilingualism in Arabic, borrowing core vocabulary and some aspects of morphology and syntax. The Northern Songhay languages of the central Sahara have been even more profoundly affected by a history of multilingualism and language shift involving Tuareg, Songhay, Arabic, and other Berber languages, much of which remains to be unraveled. These languages have borrowed so extensively that they retain barely a few hundred core words of Songhay vocabulary; those loans have not only introduced new morphology but in some cases replaced old morphology entirely. In the southeast, the spread of Arabic westward from the Nile Valley has created a spectrum of varieties with varying degrees of local influence; the Saharan ones remain almost entirely undescribed. Much work remains to be done throughout the region, not only on identifying and analyzing contact effects but even simply on describing the languages its inhabitants speak.
All through their history, Romance languages have been variously influenced by Arabic and Hebrew. The most relevant influence has been exerted by Arabic on Ibero-Romance and Sicilian in the Middle Ages, from, respectively, the Umayyad conquest of al-Andalus (711–716) and the Aghlabid attack on Sicily (827). Significant factors favoring Romance–Arabic contact have also been trade in the medieval Mediterranean (especially between Italy and the Crusader States), scientific translations from Arabic into Latin (notably those made in 13th-century Castilia), and medieval and early modern travelogues and pilgrimages, whereas of lesser importance are more recent lexical exchanges due to colonialism in North Africa and immigration, which have had a considerable impact on French. As for Hebrew, its influence has been quantitatively less relevant and mostly mediated through other languages (Greek and Latin, the Judeo-Romance languages, English). Still, it is of capital importance on a cultural level, at least as far as biblical loanwords shared by all Romance languages are concerned. Effects of Semitic influence on Romance are almost exclusively limited to lexical borrowing, in the form of both loanwords and loan translations, regarding several semantic fields, such as agriculture, architecture, clothing, medicine, natural sciences, and seafaring (Arabic); religion and liturgy (Hebrew); and anthroponomy (Hebrew and Arabic). Only in individual dialects does structural interference occur, as is the case with pantesco, the Sicilian variety of Pantelleria, which shows traces of both phonological and syntactic contact-induced changes. Finally, though not belonging to the Romance linguistic family, a very peculiar case is represented by Maltese, the Semitic language of Malta that, throughout its history, has been strongly influenced by Sicilian and—to a lesser extent—by Italian both in its lexicon and in its grammar.