[AdhemarVandamme]

I don’t see why the grammatical cases of Latin and German matter in the interpretation of these abbreviations.

The Latin prepositions cum (with) and sine (without) are always followed by the ablative case. German has grammatical cases too, but no ablative. The German propositions mit (with) and ohne (without) are followed by the accusative case.

So c.t. = cum tempore = mit Zeit = with time (or with some delay), and s.t. = sine tempore = ohne Zeit = without time (or without delay).

[filmor]

"mit" is followed by dative in German. In Latin, ablative and dative are very close and which is very close, a lot of forms are indistinguishable.

That doesn't change anything else you said, though :)

[thaumasiotes]

While it's true that many Latin nouns have identical dative and ablative forms, tempus isn't one of those nouns. (In the singular. I think dative and ablative are identical in the plural for every noun.)

And of course, as everyone has already mentioned, spookie's comment is complete nonsense because the case is required, and fully explained, by the prepositions.