Over the past nine years of regularly teaching a course in the history of the English language, I have become increasingly interested in the nature of the metaphors we use to talk about language, especially (although not exclusively) in the context of historical linguistic development and language relatedness.
An English guy named William Jones (1746-1794) usually gets the credit for suggesting that similarities among languages in Europe and in western and central Asia (Sanskrit, ancient Greek, and Latin were Jones’s particular interests) could be explained by a common linguistic ancestor. As the story generally goes, Jones, who spent much of his professional life in India as a supreme court justice, presented the common-ancestor hypothesis at a 1786 meeting of the Asiatic Society, a scholarly society that he founded in 1784. The theory has since become known as the Indo-European (IE) hypothesis and the posited common-ancestor language as Proto-Indo-European (abbreviated delightfully as PIE), although Jones’s role in the development of the Indo-European hypothesis is not universally accepted and has been disputed by some scholars.
There are no surviving PIE speakers, and they left no written records themselves, hence the need to work backwards from the oldest surviving texts in languages believed to be related to PIE to try to reconstruct what PIE itself might have been like. The phonologies – speech-sound systems – of languages that no one speaks anymore (and that no one has spoken in centuries) have to be theorized on the basis of orthography, i.e. the writing systems of the descendant languages. This can actually work pretty well for languages with alphabetic writing systems that function effectively as visual representations of sound. This is not the case for present-day English, which is well known for the nonphonetic spelling system it has developed over the past several hundred years. (More about this comparative method below.)
In the 19th century, research in historical linguistics took a Germanic turn (in several senses) when German and Scandinavian philologists took up the topic of language relatedness. The interest of German(ic) linguists in the Indo-European hypothesis was a lucky turn for anyone who might have been hoping for a lot of new knowledge about the English language because these fellows had a tendency, not surprisingly, to focus on Germanic languages, which include English.
The awesomely named Franz Bopp (1791-1867), a German linguist, further developed the Indo-European hypothesis by considering Indo-Iranian (Persian) and Germanic languages along with Sanskrit, Greek, and Latin in an 1816 monograph that may or may not have been as long as its title, which was Über das Conjugationssystem der Sanskritsprache in Vergleichung mit jenem der Griechischen, Lateinischen, Persischen und Germanischen Sprache (“On the Conjugation System of Sanskrit in Comparison with that of Greek, Latin, Persian, and Germanic”).
Rask published his first book, Introduction to the Grammar of the Icelandic and other Ancient Northern Languages (1811), at age 23 and wrote at least a dozen more during a short life that ended about a week before his 45th birthday. He wrote on a wide variety of linguistic and literary topics, especially on Germanic languages like Old English, Modern English, Frisian, Old Norse, Faroese, and his native Danish, but he also wrote books on Spanish, Italian, Sinhalese (spoken widely in Sri Lanka), Avestan (an ancient member of the Indo-Iranian branch of the IE family), and North Saami, a non-Indo-European language spoken today by about 25,000 people in northern areas of Finland, Norway, and Sweden, among others.
That guy, Jacob Grimm (1785-1863), was a German linguist and collector of folktales (yes, it’s that Jacob Grimm). He elaborated on the sound shift that Rask had previously articulated and described it in the second (1822) edition of Grimm's Deutsche Grammatik (German Grammar). The shift is known today as Grimm’s Law. I won’t bore you with the details – I’ve spent the past nine years visiting that upon my poor students – but the short version is that Grimm's Law explains why Germanic languages (including English) tend to pronounce certain sounds in words inherited from PIE differently from how they are pronounced in other (non-Germanic) Indo-European languages.
Latin pater --> English father
Latin tres --> English three
Latin centum --> English hundred
Latin baculum --> English peg
Latin dentis --> English tooth (also demonstrates PIE [t] --> Germanic [θ])
Latin gelū --> English cold
So, fast-forward 138 years from the establishment of Verner's Law, and we have a ton of good information now about the history and relatedness of Indo-European languages and the place of Germanic languages, including English, in the IE family. But the idea of PIE itself still remains mostly a metaphoric prop. It is more a way to try to make sense of something that so far remains firmly in the 'unknowable' column (although it sees plenty of action in the 'theorizable' column) than an actual unified language that was actually spoken by actual people at some actual point in time.
As a language variationist by training, meaning as someone who conceptualizes variation and change as constant and defining features of living languages, I sometimes find it hard to justify (to myself, even) some of the compromises I have to make in order to teach concepts that can otherwise be difficult for students (and for me) to get their heads around. I do try to be up front about it, though, and explain to the students that I am asking them to join me in suspending our disbelief, that I think it's important for us to be conscious that we are in fact having to suspend disbelief and also for us to talk about why we have to, and that I haven't yet been able to figure out a way for us not to have to.
When we talk about PIE, we are going for convenience, for the short version, using a word (PIE) or a phrase (Proto-Indo-European) that refers not to a single, discrete language (if there even is such a thing) but to a multitude of meanings -- overlapping, complementary, contradictory -- to save us the time and trouble of stopping and pondering what all is contained within that word or phrase because if we did stop to ponder it, there's a good chance that we would never have time for anything else.
So PIE is a relief, a tool, a technological development that saves us the trouble of risking a time-consuming mind-blow every time we need to refer to what were probably a lot of different ways of speaking that varied across space, probably to the tune of thousands of miles, and over time, possibly even thousands of years, but that still are somehow, at least metaphorically, one. And not just any one, but for us the one: Proto-Indo-European, the one that gave rise to so many other ones: Greek, Bengali, Portuguese, Czech, Kurdish, Icelandic, Hindi, Spanish, Russian, Armenian, Yiddish, Latin, Afrikaans, Welsh, Catalan, Pashto, French, and English, to name a few. Some of them are still living and some are lost to the past, but even many of those lost languages have traces remaining somewhere in the approximately 440 Indo-European languages spoken in the 21st century by literally half the population of the planet Earth.
I think about this metaphor and ask the students to think about it (and about others we use in class) as a kind of "rounding off," roughly analogous to the way that we can do quick mathematical calculations of large numbers by rounding them off, trading off precision for speed and getting somewhere that probably isn't anywhere near close enough but we pretend it is because we have no choice. One metaphor explains another.
But there had to have been variation during the millenia that PIE is hypothesized to have been extant because there is always variation. Even in a classroom with 30 people in it, of whom 25 have lived their whole lives so far within a few hundred miles of one another, there is always significant variation. The students usually don't notice that much of it at first; like all speakers of all languages, they have spent their whole lives becoming proficient at instantaneously distinguishing between differences they need to pay attention to and the ones they can ignore. But in only a few short months, most of them become very, very good at noticing and describing even relatively slight differences among speakers.
On the other hand, the variation within what we conceptualize as 'PIE' was probably over time and across locations so great as to have meant mutual unintelligibility among its (possibly imaginary) speakers. So in essence, in teaching the Indo-European hypothesis, I am asking the students to imagine and accept as a kind of reality an idealized version of a language that nobody ever really spoke, to make a deal with me to treat the abstract as absolute, even though we know it isn't. Not even close. And yet.
Our metaphoric treatment of the Indo-European hypothesis does not end here, although I am going to end the post here because as usual I have no answers. Historically, the mysterious metaphorical magic of the Indo-European hypothesis is just getting started. So please see "Let them eat metaphors, Part 2: Darwin and Schleicher Sitting in a Tree," in which we consider August Schleicher's 1861 reconstruction of Proto-Indo-European and the enduring power of biological metaphors for language.