The development of skin pigment variation and linguistic variation are explainable through adaptation theory.
Pigmentation initially was dark for all homo sapiens, gradually lightening as populations moved into areas with less and less ultraviolet radiation from the sun (i.e., northern European areas, Russia, etc). Remember, this took place over thousands of years, but may have been jump-started in areas that experienced mass die-offs during glacial expansion or catastrophic events (volcanic eruptions, tsunamis, etc).
Linguistic variation is due to similar adaptive needs. I believe the book The Throwing Madonna goes into some detail on this. The gist of it is that sounds and speech patterns that were more readily usable by the majority of a population would have been selected for repeated use over time, whereas sounds and speech patterns only used by select members of a population would have died off. The esoteric and eclectic does not survive as well as the mainstream.
EDIT: This is my expert friend's reply to your question. I believe you'll find it quite intriguing.
Oh! Great question! Well, back in the day leading creationist Louis Agassiz believed that the different "races" had been SEPARATELY CREATED by god! I'll leave you to infer which "race" he considered superior based on this patently racist scheme--hint: the idea was that it was a most UNEQUAL creation.
But the Modern Creationist has long accepted monogenism (the notion that ALL humans come from ONE source). Therefore, he/she must essentially accept the *basic* (and I mean VERY basic) explanation which has been guided by modern EVOLUTIONARY science: genetic drift (what genes just-so-happened to end up where), and local adaptation (white skin is good for areas like Central Asia [where the "white race" probably originated, it's a misconception that white=European] and of course Europe because it promotes Vitamin D absorption; dark skin is better in hot climates because it protects you from sunburn and skin cancer; epicanthic fold seen in various Asian/some Native American populations was originally a COLD-WEATHER adaptation to protect the eyes), plus whatever else (blue eyes, for example, may have spread due to sexual selection, which may also have played a role in other racial/ethnic traits' spread).
To get more specific, though, if you're a stickler for biblical literacy you HAVE to believe that the human race underwent a MASSIVE founder effect due to the ridiculous bottleneck caused by the Noah flood--I mean, the Bible SAYS it was just those eight people on the ark, Noah plus Mrs. Noah and their three sons and THEIR wives.
What this means is that ALL people are descended from those eight--but since Noah was already what, five HUNDRED years old, what it REALLY means is that we're all descended from Noah plus Mrs. Noah by WAY of their three sons. Now this is where it gets REALLY interesting (I mean ZANY): what a lot of creationists have been saying for AGES is that there are three "races" descended from each of the three sons, albeit with probably some cross-over. So I think you'll find a lot of 'em saying that Ham begat the "black race" of Africans (which is probably the stupidest part of this scheme since the so-called "black" sub-Saharan Africans are more genetically diverse than the rest of the entire world COMBINED), Japheth begat the "white race" (all us Euros) and Shem begat the Middle Easterners (which is also very stupid when you consider the amount of interchange between the Middle East and practically every adjoining and even non-adjoining region) and--and this one is probably the biggest "gas" other than the Ham thing--most Asian/Pacific Islander/Native American peoples AS WELL!
I'm sure by this point you're laughing hard enough to practically **** yourself (or you're speechless with rage over the stupidity and quite-implicit-racism [remember the "Tribes of Ham" justification for "black" slavery?]). But in all fairness I should point out that creationists are divided into Young Earth/Old Earth types. So some of 'em may say that the above scenario (which is actually the one that my "history" textbook at my private Christian "school" enjoined) is false: that it was more like ALL humans spreading out after the Tower of Babel with no regard to which son of Noah they were descended from.
Okay, Weapon Number One: the Bible actually spells out the genealogies of the sons of Noah in Genesis 10. Guess who Ham's descendants are?
"6 The sons of Ham were Cush, Mizraim, Put,[c] and Canaan. 7 The sons of Cush were Seba, Havilah, Sabtah, Raamah, and Sabtechah; and the sons of Raamah were Sheba and Dedan.
8 Cush begot Nimrod; he began to be a mighty one on the earth. 9 He was a mighty hunter before the LORD; therefore it is said, “Like Nimrod the mighty hunter before the LORD.” 10 And the beginning of his kingdom was Babel, Erech, Accad, and Calneh, in the land of Shinar. 11 From that land he went to Assyria and built Nineveh, Rehoboth Ir, Calah, 12 and Resen between Nineveh and Calah (that is the principal city).
13 Mizraim begot Ludim, Anamim, Lehabim, Naphtuhim, 14 Pathrusim, and Casluhim (from whom came the Philistines and Caphtorim).
15 Canaan begot Sidon his firstborn, and Heth; 16 the Jebusite, the Amorite, and the Girgashite; 17 the Hivite, the Arkite, and the Sinite; 18 the Arvadite, the Zemarite, and the Hamathite. Afterward the families of the Canaanites were dispersed. 19 And the border of the Canaanites was from Sidon as you go toward Gerar, as far as Gaza; then as you go toward Sodom, Gomorrah, Admah, and Zeboiim, as far as Lasha. 20 These were the sons of Ham, according to their families, according to their languages, in their lands and in their nations." (Genesis 10: 6-20, NKJV).
Source: http://www.facebook.com/l/c504d;www.biblegateway.com/passage/?search=Genesis+10&version=NKJV
Whoo-eeh! What a LAUNDRY LIST of practically everyone the Hebrews looked down on--plus some more, ALL OF WHICH supports the "Hamitic hypothesis" for the origins of Africans and, in fact, some of the Middle Eastern peoples the Hebrews were enemies with! Here we have Cush (that'd be the Nubians, so northern Sudan up into Egypt) Mizraim (that's the Hebrew name for Egypt), Put aka Phut (that'd be modern-day Horn of Africa, which the Egyptians traded with down the Red Sea--think modern-day Somalia/Djibouti area essentially), Canaan (evidence of Biblical bullshit--the Hebrew WERE CANAANITES), Babel aka Babylon/Erech/Accad aka Akkand/Calneh in the land of Shinar (what the Hebrews called Babylonia) and ASSYRIA!
How about Japheth? More bullshit:
2 The sons of Japheth were Gomer, Magog, Madai, Javan, Tubal, Meshech, and Tiras. 3 The sons of Gomer were Ashkenaz, Riphath,[a] and Togarmah. 4 The sons of Javan were Elishah, Tarshish, Kittim, and Dodanim.[b] 5 From these the coastland peoples of the Gentiles were separated into their lands, everyone according to his language, according to their families, into their nations. (Genesis 10: 2-5, NKJV).
Right there you have the infamous Sea Peoples and by extension, all of the Mycenean/Aegean/Anatolian folks i.e. Greeks, Hittites if I'm not much mistaken. "Coastland peoples of the Gentiles" says it all. Basically this is where the Hebrews thought us Indo-Europeans came from (although I honestly don't know if this includes the Indo-Iranian peoples, who ARE Indo-European).
And Shem:
21 And children were born also to Shem, the father of all the children of Eber, the brother of Japheth the elder. 22 The sons of Shem were Elam, Asshur, Arphaxad, Lud, and Aram. 23 The sons of Aram were Uz, Hul, Gether, and Mash.[d] 24 Arphaxad begot Salah,[e] and Salah begot Eber. 25 To Eber were born two sons: the name of one was Peleg, for in his days the earth was divided; and his brother’s name was Joktan. 26 Joktan begot Almodad, Sheleph, Hazarmaveth, Jerah, 27 Hadoram, Uzal, Diklah, 28 Obal,[f] Abimael, Sheba, 29 Ophir, Havilah, and Jobab. All these were the sons of Joktan. 30 And their dwelling place was from Mesha as you go toward Sephar, the mountain of the east. 31 These were the sons of Shem, according to their families, according to their languages, in their lands, according to their nations. (Genesis 10: 21-31, NKJV).
Elam is easy: that'd be the Elamites, a sophisticated urban civilization originating in the Khuzestan lowlands in what is now the southwestern-most corner of Iran, RIGHT smack-dab east of ancient Sumer (in southern Mesopotamia) who were essentially the very first urban civilization to dominate the lands across the Zagros Mountains into the Iranian Plateau. The Medes and Persians took their cues from the Elamites, absorbing their civilization as they founded their respective empires.
Oh, but wait! We also have ASSHUR aka Assyria: so perhaps the Assyrians are Semites AND Hamites. Arphaxad and Lud I'm not sure, but Aram refers to the Arameans--basically a Greater Syrian trading culture who were the land-based equivalent of the famous Phoenicians. Aramaic, their language, was picked up by the Assyrians and later the Babylonians and still later the Persians--so it was a lingua franca/trade language that became an administrative language. Mesha/Sephar/mountain of the east... I don't know, but I SUSPECT, again, that this refers to the Zagros Mountains of Iran and Iraq.
Weapon Number Two: genetically, this scenario is absurd. Sub-Saharan Africans are more diverse than all the rest of us (RIDICULOUSLY so). If you trace the mitochondrial DNA and Y-chromosome lineages, you'll find very different scenarios--and basically everything we know about history and linguistics (which allows us, as you probably know, to reconstruct enti