This will be something to ponder for the weekend. It's another crazy idea I had that may not be so crazy. Let me just first spit out the revelation I'm having and I'll explain it all afterwards.
I will start with the claim that Proto-Semitic originated from the Syria-Palestine area, rather than from Southern Arabia as has been so often claimed. Then, considering the well-known fact that Neolithic innovations originated from Western Asia and only later spread into Europe, I'm going to suggest that Proto-Semitic speakers were not only people with agricultural know-how, but that their language became a vibrant trading language well beyond their immediate area. What I'm suggesting is that multilingualism was not only common during the Neolithic but even vital for communities and their material well-being. I don't know why I didn't clue in before, but if Proto-Semitic speakers were ahead of everyone in terms of technology, naturally their language too might become a hot commodity. And if knowing that language was in demand for trade, then it follows that there were large areas surrounding the immediate Proto-Semitic language area where people would have adopted Proto-Semitic as a second language!
Think about it now. Around 5500 BCE, speakers of "Mid Indo-European" (MIE), ancestral to later Proto-Indo-European (PIE), might have been situated further into the Balkans to take advantage of goods coming in from the south, perhaps along the coastline, and these people would have been at least semi-fluent in Proto-Semitic in order to communicate with the incoming traders. (I mean, how else could they likely communicate with each other other than becoming bilingual?) The Syria-Palestine area was afterall a center for agriculture and we know that there are words in Proto-Semitic relating to agriculture as the American Heritage Dictionary explains in detail: "There are many Proto-Semitic terms referring to agriculture, which was a significant source of livelihood. Words for basic farming activities are well represented: fields (*ḥaql-) were plowed (*ḥrθ), sown (*ðrʕ), and reaped (*ʕƛd); grain was trampled or threshed (*dyš) and winnowed (*ðrw) on a threshing floor (*gurn-), and ground (*t’ḥn) into flour (*qamḥ-)." As for multilingualism in ancient communities, this shouldn't be much of a shocker considering the examples of Quechua and Swahili. Multilingualism was much more common in ancient times than we often appreciate.
My idea hopefully will raise mindteasing issues concerning the loanwords in PIE. Are they really the product of direct Proto-Semitic contact or is it even more direct than I thought. That is, are these loanwords rather the natural result of generations of bilingual speakers of both languages? Bilingual interference like this happens all the time and I can speak with authority on that, being bilingual, that it is a common tendency for two languages that reside in your brain to jumble together sometimes, producing spontaneous loanwords. I remember the time I accidentally blurted out the word *distach instead of detach while talking to a friend. I realize now that this was because of a subconscious mental association between the French prefix dé(s)- and English de- or dis-. Even though my native language is English, French obviously had an affect on me. It only took a second for my tongue to say it, but hours to reflect on the implications of my dysphasic faux pas. Unlike in the modern age of grammatical simulacra, there would be no anal-retentive grammarian in the Neolithic to stop a bilingual person whose mother language was PIE from slipping up now and then, using a Semitic word for a PIE word that he or she may have momentarily forgot. It would only be a matter of time for the products of this language switching to become normalized in a community and spread to neighbouring communities.
I have tonnes more ideas on this, such as the "borrowing hierarchy" issues in relation to intensive language contact which were brought up in Elsik and Matras' Markedness and Language Change: The Romani Sample (2006) which I cited in an earlier post, but I'll just have to take this one blogpost at a time. Breathe in, breathe out, breathe in... Hehe.
 Lipinski, Semitic Languages: Outline of a Comparative Grammar (2001), p.43 (see link): "Since the Semitic languages go apparently back to a common origin, the question of the location of the speakers of this Proto-Semitic language has been often considerederd of importance. Various regions have been taken into account: Syria, Arabia, and Africa." Sadly, Lipinski seems to overrely on geographical names to draw a conclusion about the likelihood of Semitic speakers in Syria. He seems here to be ignoring or is ignorant of the important issue of Semitic loanwords in PIE altogether.
(March 14 2008) I should just clarify something just in case people incorrectly add two plus two together to make five. The graphic above is not meant to endorse in any way the "Out-of-Anatolia" fringe hypothesis promoted by Gamkrelidze and Ivanov, which is in my view assuredly wrong. I've been convinced by Alan Bomhard's view that Indo-European originally came off the steppelands of Western Asia from the east. However, I'm tossing around a new idea that Late IE was largely an offshoot of northern Mid IE dialects (although I haven't the foggiest idea how I could prove this!).