We use apropos to start a new point that still belongs to what was just said — a polite way of turning the talk a little, without jumping into a totally new world. You will hear it in careful speech and in writing that wants to sound thoughtful: “Apropos of your question about trains…” or “Apropos the budget, we should talk about paper too.” Friends chatting over lunch are more likely to say “speaking of that” or “that reminds me”; apropos still feels a bit French and a bit formal.

We use apropos to start a new point that still belongs to what was just said我們用apropos來開啟一個新的重點，但這個重點還是跟剛才講的話有關 — a polite way of turning the talk a little這是一種有禮貌地稍微轉個話題的方式, without jumping into a totally new world而不是直接跳進一個完全不相干的話題。You will hear it in careful speech and in writing that wants to sound thoughtful你會在講究的談話、或想聽起來很有想法的文章裡聽到它: “Apropos of your question about trains…”『Apropos of your question about trains…（說到你問的火車那件事……）』 or “Apropos the budget, we should talk about paper too.”或是『Apropos the budget, we should talk about paper too（說到預算，我們也該談談紙張的部分）。』 Friends chatting over lunch are more likely to say “speaking of that” or “that reminds me”朋友吃午餐聊天時比較可能會說『speaking of that』或『that reminds me』; apropos still feels a bit French and a bit formalapropos聽起來還是有點法文味、有點正式。

Though actually, people also say “apropos of nothing” and then start a subject that is not linked at all — they are marking the jump on purpose.

Though actually不過事實上, people also say “apropos of nothing” and then start a subject that is not linked at all人們也會說『apropos of nothing』，然後開始講一個完全不相干的話題 — they are marking the jump on purpose他們是故意標示出這是個跳躍的話題。

The same word can mean “about / concerning”, and as an adjective it can mean “said at the right moment” (“a very apropos remark”). That last use feels close to appropriate, and the two words look related, but they did not come from the same Latin parent — they just grew up looking alike.

The same word can mean “about / concerning”這個字也可以當作『about／concerning（關於）』來用, and as an adjective it can mean “said at the right moment”當形容詞時，它可以指『在對的時機講出來的』 (“a very apropos remark”)（『a very apropos remark（一句非常貼切的話）』）。That last use feels close to appropriate最後這個用法感覺很接近appropriate, and the two words look related而且這兩個字看起來很像, but they did not come from the same Latin parent但它們並不是來自同一個拉丁字源 — they just grew up looking alike只是碰巧長得很像而已。