There is a recent question asking when the grammar of some language ancestral to English branched a certain feature. Since it garnered many votes, I suppose it was on-topic.
Which languages are on-topic? Can I ask about Proto-Germanic morphology?
That question is on-topic because it is asking about English; the fact it compares English with Dutch and German doesn't make the question off-topic because the OP is interested to know if a similar construct was present in English. Dutch and German have not been chosen as random examples: English, Dutch and German are three Germanic languages.
The question would have probably been off-topic is it was asking how to translate, for example, a sentence from Spanish to English.