Proto-Indo-European had a suffix –je/o– that was attached to some verb roots. I recently realized that the translation of such –je/o– verbs in English usually requires a preposition. I believe such a prepositional value was the meaning of this –je/o– suffix. Here are a few examples:
spekj-je/o– “look at”
seh2g-je/o– “look for, seek”
ghwedh-je/o– “pray to”
legh-je/o– “lie down on”
It seems to me that these verbs would probably have taken the dative case in Proto-Indo-European, rather than the accusative case. Here are the verbs above used with objects in the dative case:
spekjjō kjunei – “I look at a dog” (not “I look a dog”)
ghwedhjeti deiwōi – “He prays to a god” (not “He prays a god”)
The Germanic preterite-presents are a small group of special verbs in which the present tense continues the Proto-Indo-European perfect.
A clear example of the sense development of these verbs can be seen in the verb *witaną “to know”. The 1st person singular of the present indicative of this verb was *wait “I know”. This developed from PIE *woid-h2e “I have learned” which is the perfect of the verb root *weid– whose meaning was “to learn”. The same development is seen in Greek oida “I know” – also from *woid-h2e. The meaning of *witaną “I know” developed from the meaning “I have learned”.
The other Germanic preterite-presents can be understood similarly. Another example is the verb *duganą “to be useful”. This verb derives from the perfect of a PIE verb root *dheugh– which I believe meant “to help”. The sense development here is that if something has helped, it is useful. By the way, the PIE word for “daughter” – *dhugh-tēr – is derived from this root. Its original meaning was “helper”, specifically “(mother’s) helper”.