To understand Arabs and their culture, one must first understand their language, but with many conflicting theories about its origins, this is no easy task.

To celebrate a language used by hundreds of millions of people around the world, ­December 18 is the designated UN Arabic Language Day. The day was established by the UN ­ Educational, Scientific and ­Cultural Organisation (Unesco) in 2010 to “celebrate multilingualism and cultural diversity as well as to promote equal use of all six of its official working languages throughout the ­organisation.”

This date was chosen because it was the day in 1973 when ­Arabic became the sixth official working language of the General ­Assembly of the United Nations and its main commissions – the others being Chinese, English, French, Russian and Spanish.

“Arabic is a very rich language; it has different dialects and different calligraphic forms and styles,” says Hasan Al Naboodah, an Emirati historian and dean of the College of Humanities and Social Sciences at the UAE ­University in Al Ain. “Its history is as complex as the history of the countries that use the language.”

There are four major regional dialects of Arabic spoken in the Arab world today, with dialectic variations in different countries: the Arabic of the Maghreb (North Africa), Egyptian Arabic (Egypt and Sudan), Levantine ­Arabic (Lebanon, Syria, Jordan and ­Palestine), and Iraqi/Gulf ­Arabic.

According to various sources, the first manifestations of the language appear to go back to the second millennium BC. Arabic belongs to the Semitic family of languages, which also includes Hebrew, Aramaic and ­Phoenician.

Other languages have used the Arabic script – Hausa, Kashmiri, Kazak, Kurdish, Kyrgyz, Malay, Morisco, Pashto, Persian/Farsi, Punjabi, Sindhi, Tatar, Turkish, Uyghur and Urdu – although some of these have switched to Latin script.

“Quraish of Mecca are said to be the first to speak Arabic ‘Fos ha’, and so the Quran today is that of the dialect or style of reading that Prophet Mohammed used ­himself,” Al Naboodah says.

This form of Arabic goes back to pre-Islamic poetry and is an elegant, or clear, form of Arabic. Muslim scholars say that initially the Quran was revealed by God and taught by the ­Prophet ­Mohammed in seven types of ­qera’at (readings). At the time, they were the most dominant dialects in spoken Arabic.

Many years after the Quran was made into a book, a copy owned by Uthman ibn Affan, a companion of Prophet Mohammed and the third Caliph of Islam, had the Arabic letters dotted. Diacritics such as tashkeel or formations were added, including harakat motions or vowel marks, as well as various tone and pronunciation grids to unify and standardise it.

“Some say Arabic script originated from Al Hirah (fourth-to-­seventh-century Mesopotamia) in the north, while others say it originated from the south of ­Arabia, from Himyar (110 BC to AD 525),” Al Naboodah. “The origin of Arabic is a highly debated topic, with new discoveries still happening.”

A discovery in 2014 by a French-Saudi expedition team hailed “the oldest known inscription in the Arabic alphabet” at a site located near Najran in ­Saudi Arabia. The script, which was found on stelae (stone slabs) that has been preliminarily dated to AD 470, corresponds to a period in which there was a missing link between Nabataean and Arabic writing.

“The first thing that makes this find significant is that it is a mixed text, known as ­Nabataean Arabic, the first stage of ­Arabic writing,” says epigrapher Frédéric ­Imbert, a professor at Aix-Marseille ­University.

The Nabataean script was developed from Aramaic writing during the second century BC and continued to be used until around the fourth or fifth century. Nabataean is therefore considered the direct precursor of the Arabic script. Nabataean script is a close ancestor, and the Najran style is the “missing link” between Nabataean and the first “Kufi” inscriptions.

Until this discovery, one of the earliest inscriptions in the ­Arabic language was written in the ­Nabataean alphabet, found in Namara (modern Syria) and dated to AD 328, on display at the Louvre in Paris.

The history of Arabic continues to be debated. Modern standard ­Arabic is different from Quranic as well as from classical Arabic. It has gone through a process of “Europeanisation” that changed parts of the vocabulary and also deeply influenced the grammar.

“Linguistic evidence seems to point to an origin of the Semitic languages somewhere between the Fertile Crescent [an area that spanned the top of the Arabian Peninsula from Egypt to Syria and Kuwait] and the Arabian ­Peninsula,” says Stephan Guth, professor of Arabic language and Middle Eastern literatures at the University of Oslo.

Over millennia, these languages spread, as different groups left their homelands, carrying their languages with them into various parts of the Middle East and neighbouring areas.

“A language is a continuum with many different stages of development, many of which may be addressed (and actually are addressed) by individual names, and it depends on the criteria that you decide to make decisive,” Guth says.

“The main challenge in writing a history of Arabic is that there is only little written evidence for what probably is the larger part of its history, and that for the period dating before pre-Islamic poetry we only have unvocalised material, so that we only can guess or try to reconstruct with linguistic methods, but rarely be 100 per cent sure how things ­actually were pronounced. There are some hints from languages that were in contact with Arabic and wrote the vowels (Akkadian, Greek, Latin), but the material is scarce and often only some names,” he says.

Guth says that the most recent study, by Leonid Kogan in 2015, dealing with the question of internal grouping within the Semitic language family places Arabic according to two principles:

Genetically the chain moves from ­Proto-Semitic to West ­Semitic to Central & Ethio-­Semitic to Central Semitic to ­Arabic. This implies that genetically ­Arabic would be a “sister” language of other ­Central Semitic languages, like Hebrew and the Aramaic (Aramoid) group.

However, Guth says, because of geographical vicinity, which caused language contact and influence beyond the Central Semitic “genes”, Arabic also shares a lot of features with the languages in the South, particularly Classical Ethiopic (Geez).

“As for non-Semitic influences, they have always been there (but also Arabic influenced the others), as always happens when people are in contact. All the long political and cultural history that Arab people have gone through is reflected in the language.”

The professor explains: “In pre-Islamic times you find borrowings from Akkadian, ­Aramaic, Ethiopic, South ­Arabian, Greek, Latin; after the conquests, when the Arabs came into contact with other people, there is, for example, a lot of Middle Persian and ­Turkish, and in early Abbasid times, when you had the Bayt Al Hikma in Bagdad, where all the translations were made, there is a heavy influx of classical Greek. Later on, contacts with the ­Mediterranean intensified, so the language was enriched by words from Italian and so on.

“Not to speak of the colonial period and the 19th century when European cultural domination became so strong that larger parts of the vocabulary had to be invented, or adapted (and also grammar changed to a certain extent); today, it is mainly English and (in the Maghreb) French that are major sources of borrowing,” Guth says.

As for dialects, he says: “Well, this is a chapter in its own right.”

So as the world celebrates Arabic on Sunday, it heralds a complicated language, its story difficult to reconstruct because historic truth is still much shrouded and obscured by legends and myths.