Was The Flood A Semite Immigration Metaphor?

Maju made this comment as part of a larger comment on January 8, 2013 12:03 AM at Ethio-Helix:

[I]n the 4th millennium BCE, at the edge of History, they expanded quite suddenly into the agricultural regions around their semi-desertic econiche (the mythical "flood", which is probably a wordplay in Sumerian between amaru=flood and a-maru=semites, also known as amurru). I can only imagine that climatic conditions were at play but whatever the case this is pretty much documented archaeologically and, in the case of Sumer, also in text (only "after the flood" Semitic names begin to appear).
 

The Semites who did this are commonly known today as the Akkadians, and at about the time indicated by Maju their language replaced Sumerian as the language of the string of city-states along Mesopotamia.  There are about 1500 years of Sumerian language writing before this language shift in Mesopotamia (ca. 3500 BCE to 2000 BCE), after which Sumerian survived solely as a liturgical language until about the 1st century CE.  But, the transition took time an preceded the unification of the Akkadian Empire:

Speakers of the Akkadian language seem to have already been present in Mesopotamia at the dawn of the historical period, and soon achieved preeminence with the first Dynasty of Kish and numerous localities to the north of Sumer, where rulers with Akkadian names had already established themselves by the 3rd millennium BC. Sargon has often been cited as the first ruler of a combined empire of Akkad and Sumer, although more recently discovered data suggests there had been Sumerian expansions under previous kings, including Lugal-Anne-Mundu of Adab, Eannatum of Lagash, and Lugal-Zage-Si.

The linguistically Akkadian period was interrupted by a period of rule by Kassites from the neighboring moutains, which lasted about four centuries until roughly the point of Bronze Age collapse (ca. 1200 BCE).

The Neo-Assyrian Empire that emerged after Bronze Age collapse, and the Neo-Babylonian empire that followed, were apparently run by Akkadian language speakers although Aramic began to emerge around this time.  In the 6th century BCE, much of Mesopotamia came under the rule of Cyrus the Great, a linguistically Indo-European Persian King, but apparently the common people of that time and place spoke the Semitic Aramaic language thathad  superceded earlier Akkadian dialects within a century or three of Bronze Age collapse.

Arabic, of course, became the language of Mesopotamia, around the 7th and 8th centuries CE with the rapid expansion of the Islamic empire and has remained so ever since then. 

Some languages closely related to Akkadian are attested in written form in what is now Syria, more or less, which had a somewhat less elaborate level of political organization at the time and is often viewed as the place of origin of the Akkadians in Mesopotamia.  These are the earliest Semitic languages attested in writing.

Many of the stories in the Jewish Torah (much of Genesis and some of Exodus) have antecedents in earlier Mesopotamian myths.  The deluge myth in the Torah closely parallels the language of the Mesopotamian myths and the adoption of Moses by a princess as an infant found in a basket in a river, for example, are among them.  So too are close antecedents to the Biblical Creation myth and the story of Cain and Abel. 

Modern biblical scholarship sees these parts of the Torah entering the canon during the 6th century BCE during a period of Babylonian exile for the Jewish people, but a deeper link via legends assimilated by Semitic peoples in the Akkadian empire are also plausible.

I am skeptical of Maju's suggestion that the mythical flood may have been exclusively a metaphor of Semitic immigration, although this secondary meaning may have attached to the term as an intentional double meaning at some point.  The possibility that a major Sumerian river flood was the tipping point event that opened its doors to Semitic immigration, however, and that their arrival gave birth to a new culturally meaningful historical era, however, is plausible.

I do believe that Maju's take on the time that the flood myth appears may be approximately correct.  Efforts to link early Mesopotamian accounts to archaelogy point to Mesopotamian floods ca. 2900 BCE as particularly attractive candidates as the source for the Mesopotamian-Biblical flood story.  As Wikipedia explains (in the link on Mespotamian myths above):

In the WB-62 Sumerian king list recension, Ziusudra, or Zin-Suddu of Shuruppak is recorded as having reigned as both king and gudug priest for 10 sars, or periods of 3,600. In this version, Ziusudra inherited rulership from his father Šuruppak (written SU.KUR.LAM) who ruled for 10 sars. The line following Ziusudra in WB-62 reads: Then the flood swept over. The next line reads: After the flood swept over, kingship descended from heaven; the kingship was in Kish. The city of Kish flourished in the Early Dynastic period soon after an archaeologically attested river flood in Shuruppak (modern Tell Fara, Iraq) and various other Sumerian cities. This flood has been radiocarbon dated to ca. 2900 BCE. Polychrome pottery from the Jemdet Nasr period (ca. 3000–2900 BCE) was discovered immediately below the Shuruppak flood stratum, and the Jemdet Nasr period immediately preceded the Early Dynastic I period.

The significance of Ziusudra's name appearing on the WB-62 king list is that it links the flood mentioned in the three surviving Babylonian deluge epics of Ziusudra (Eridu Genesis), Utnapishtim (Epic of Gilgamesh), and Atrahasis (Epic of Atrahasis) to river flood sediments in Shuruppak, Uruk, Kish et al. that have been radiocarbon dated to ca. 2900 BC. This has led some scholars to conclude that the flood hero was king of Shuruppak at the end of the Jemdet Nasr period (ca. 3000–2900) which ended with the river flood of 2900 BC.

Ziusudra being a king from Shuruppak is supported by the Gilgamesh XI tablet (see below) making reference to Utnapishtim (Akkadian translation of the Sumerian name Ziusudra) with the epithet "man of Shuruppak" at line 23.
 

The oldest surviving written account of the Ziusudra epic is from the 17th century BCE.  After Akkadians arrive, but before the events purportedly recounted by about 1200 years.  As explained in the link related to the Sumerian King lists above:

The earliest listed ruler whose historicity has been archaeologically verified is En-me-barage-si of Kish, ca. 2600 BC. Reference to this individual in the Epic of Gilgamesh has led to speculation that Gilgamesh himself may be historical. Three dynasties are notably excluded from the list: the Larsa dynasty, which vied for power with the (included) Isin dynasty during the Isin-Larsa period; and the two dynasties of Lagash, which respectively preceded and ensued the Akkadian Empire, when Lagash exercised considerable influence in the region. Lagash in particular is known directly from archaeological artifacts dating from ca. 2500 BC. The list is important to the chronology of the 3rd millennium BC. However, the fact that many of the dynasties listed reigned simultaneously from varying localities makes it difficult to reproduce a strict linear chronology.
 

The legendary chronology as currently understood assigns 16,455 years between En-me-barage-si of Kish and the deluge flood, a conversion rate of 54.85 legendary years +/- to 1 archaeologically inferred year (about one week per legendary year).

Identification of this particular flood with the Sumerian flood myth, of course, requires many other global flood myths to be essentially independent in origin, or for this particular version of the flood myth fossilized in the earliest written legends to have been embedded and individualized within in a deeper flood myth tradition superimposing the 2900 BCE flood on a myth based on an earlier event recounted in deep oral histories.

The oldest of surviving the Sumerian King lists are dated to about 2000 BCE, about the time at which the Akkadians arrive in Mesopotamia (Sargon of Akkad's reign has been estimated at 2270 BCE in the Wikipedia entry on the Sumerian King lists).

Thus, the case for an origin of this myth (or at least the Sumerian-Akkadian-Biblical version of it) in events sometime in the Copper Age or early Bronze Age, rather than in the early Neolithic era or the Mesolithic era, is strong.

If the primary Semitic expansion out of Africa and into Southwest Asia begins perhaps about 3000 BCE, give or take a century or two, perhaps vitalized by the rise of ancient Egyptian civilization's effects on Afro-Asiatic language speakers generally, then the Afro-Asiatic languages might have been confined to Africa before then. 

Of course, earlier dates for a Semitic emergence from Africa are possible and this still doesn't explain how Egyptians and other African beneficiaries of the Fertile Crescent Neolithic revolution managed to escape superstrate linguistic assimilation with incoming Neolithic Levantine populations.  (Maju suggests that the Levant adopts Afro-Asiatic languages prior to the Neolithic revolution.)