Anyone who has had even the smallest amount of German tuition will know that, to form a past participle in German, you whack a ge- on the front (and shove a -t on the end – well, most of the time). Ever wondered where that came from? I hadn’t until I stumbled across someone writing about it when I was reading about German verbs in Lockwood’s (1968) scintillating book Historical German Syntax.
In terms of its etymology, Lockwood (1968) makes the claim that ge-, which was gi- in Old High German (henceforth OHG) and (probably) ga- in Proto-Germanic, is likely to be a cognate with the Latin cum/con-/co-, ‘with’. He reckons its primary sense was the meaning of ‘together’.
Indo-European verbs had a means of expressing how an action took place in addition to when it took place. The Linguists among you will know that the former refers to aspect, the latter to tense (see this article for info about aspect). Apparently, according to Lockwood (1968), in OHG the commonest function of ge- was to make imperfect verbs perfective.* For example, the OHG verb swîgan meant to ‘be silent’, and giswîgan meant to ‘fall silent’. There also existed some ‘simplexes’, e.g. bringan, ‘to bring’, which were already understood to be perfective, so didn’t need to take the gi- perfective prefix (think about it: if you ‘bring’ something somewhere, the action is always completed. You can’t bring me a book and the book not reach me). There were also some verbs which compounded with gi- which had no corresponding simplexes, e.g. gilouben, which is modern day glauben, ‘to believe, think’.
There are a couple of verbs which have a corresponding form with ge- on the front in modern German, e.g. denken (‘to think’) vs gedenken (‘to remember’, in the sense of commemoration). Now, however, there is a lexical difference, rather than an aspectual one. Lockwood (1968) could only come up with gefrieren (‘to freeze (up)’) as a modern infinitive with a ge- on the front which is aspectually perfective.
However, to go back to OHG, the ‘perfective preverb’ gi- was generalized to a large extent before past participles, because the use of a perfect tense often implied a completed action. Consequently, gisagêt often functioned as the past participle of both sagên and gisagên. Our perfective simplexes noted above retained the original, gi-less past participles:
ih haben iʒ funtan
‘ich habe es gefunden’
‘I (have) found it.’
This made me happy as I have often wondered why some past participles didn’t seem to have a ge– prefix in older German texts. An example that immediately springs to mind is one of the chorale/recits, no. 7, in J.S. Bach’s Christmas Oratorio: Er ist auf Erden kommen arm (something like ‘He has to earth now come so poor’). One would expect a tidy ge- on the front of kommen in modern German. Yet there isn’t one.
In Middle High German and New High German, the aspectual distinction largely died out. Hence sitzen ‘to sit’ and sagen ‘to say’ have survived, but gesitzen and gesagen haven’t. In other instances, the simplex has died out, and the ge- form has prevailed:
OHG winnan – ‘to struggle’, giwinnan – ‘to obtain by strength'; Mod. German gewinnen – ‘to win’
The ones that have survived (as in denken/gedenken above) all have a lexical difference in the modern language, as noted above. Ge- had spread to the past participles of all of the simplexes by Early New High German (ENHG), but only if the verb bore initial stress. Lots of verbs in the modern language that end in -ieren do not bear initial stress, and also take no ge- prefix on their past participles (think markiert, blamiert, arrangiert, etc).
At some point, ge- must have been reanalyzed as a tense marker of the perfect, which is hardly surprising as it was used so much in perfect constructions. Those perfective simplexes like kommen prevailed until the eighteenth century, when little ge- also took hold of them as well. There are now only traces of the old forms in words like willkommen, rechtschaffen.
*Lockwood (1968:102) notes that the presence/absence of gi- was partly determined by considerations which had nothing to do with aspect.