Why "eleven" and "twelve" and not "firsteen" and "seconteen"?
Why "firsteen" and "seconteen"??? The pattern would dictate "oneteen" and "twoteen"--or more likely "twainteen," which by now would have degraded into "twenteen," just as "twainty" became "twenty."
Why do they get their own special term and get to depart from the "teen" pattern?
More on that in a moment.
Proto-Indo-European had a word for "hundred,"
kmtom, and in fact the traditional taxonomy of the Indo-European family is based on the evolution of that word. In the Eastern subfamily the K softened to S (Russian
sto, Sanskrit
satem), while it was retained in the Western subfamily (Greek
hekaton and Latin
kentum-- spelled "centum"). We still often refer to them as the Satem Languages and the Kentum Languages--although ironically that K quickly changed into H in German
hundert, S in French
cien, CH in Italian
cento and TH in Spanish
ciento.
This indicates that the tribe had developed basic arithmetic and used the decimal system. However, they apparently had not developed a standard way of naming two-digit numbers, because none was passed down to us. Today there are myriad systems: twenty-six in English, six-and-twenty in German, twenty-and-six in Spanish, six-on-twenty in Czech, etc.
The Germanic languages are unusual (if not unique) among the Indo-European languages, for treating 11 and 12 differently from the other "teens." As Dywyddr noted, "eleven" and "twelve" are special words leftover from Stone Age counting: "one left" and "two left" after running out of fingers. This is, however, not unusual from a global standpoint. I remember reading about one of the languages of Southeast Asia or Oceania in which "eleven" is rendered literally as "now I have to go down and start using my toes."
Is this somehow tied to the special status the "twelve pattern" holds to the English world? (i.e. "dozen", twelve hours on the clock, etc.)
Not convincingly. Besides, the twelve pattern is hardly limited to the anglophone community. The reason we have the word "dozen" is that the Normans had already coined the word
douzaine, a noun formed from the number
douze. (Which is Latin
duodecem, "two-ten".) They also gave us the word "gross" for twelve dozen.
I wonder whether twelve was simply a handy number for use in business, since a dozen doohickeys can be broken up and sold separately as groups of two, three, four or six. Ten doohickeys only give you groups of two or five.
The Romans and Greeks also found twelve to be a useful number, not to mention sixty, which can be factored by 2, 3, 4, 5, 6, 15, 20 and 30! The Mayan calendar, which has lately become notorious, has a sixty-cycle, as does the Chinese lunar calendar.
Everyone who's studied French is amazed by the way they count between eighty and one hundred. 98 is read as
quatre-vingts dix-huit, "four twenties and eighteen." This suggests that the Franks might have had a
vigesimal (base twenty) number system before they were Romanized.
Similarly, dozen is two-ten (do-Zehn), though I'm not certain on its exact derivation through time.
You need to review the paradigm of phonetic shifts from Proto-Germanic into Modern German.
Zehn (which BTW is pronounced "tsane," not "zane") is the same word as "ten."
Zwei is "two,"
zahn is "tooth,"
setzen is "sit." In many positions Proto-Germanic T became German TZ; although in many others it became S:
besser = "better,"
das = "that,"
essen = "eat," etc.
the first number systems were base 12
No. Humans have always had ten fingers. There is an ancient word for ten in virtually every language family for which we have reconstructed a proto-language. Not so for twelve.
There is some suspicion that a base-five number system may have come first. The Basques are almost surely the descendants of the Cro-Magnon people, the first
Homo sapiens explorers to settle in Europe. The Basque language borrowed the Spanish word for "six."
