Mixed third/second conditional
We use this combination to talk about a hypothetical condition happening in the past (third conditional) with a present result (second conditional).
Mixed second/third conditional
We use this combination to talk about a hypothetical condition happening in the present (second conditional) with a past result (third conditional).
Tip
In mixed second/third conditionals, the hypothetical present situation is assumed to have also been true in the past, impacting a past outcome.
For example, in the sentence: “I would have understood them if I spoke German.”, the speaker implies that they didn’t speak German in the past when they wanted to understand the other people.
References