Translation guide
Used to add a stronger or more obvious point to an already stated one, meaning 'not to mention' or 'let alone'. In Japanese, this is expressed with particles and phrases that emphasize the obviousness of the second item.
Adding a stronger or more obvious point to emphasize the extent of something
A common pattern meaning 'not only A, but also B' or 'A, to say nothing of B'. A is the more obvious or expected, B is the additional point.
彼は英語はもちろん、フランス語も話せる。
He can speak French, to say nothing of English.
このレストランは味はもちろん、サービスも素晴らしい。
This restaurant has great service, to say nothing of the taste.
Similar to はもちろん, but slightly more formal. Used in written or formal speech.
この問題は国内はもとより、国際的にも注目されている。
This issue is attracting international attention, to say nothing of domestic.
Used to say 'far from A, even B'. Emphasizes that B is even more true or extreme. Often used when A is expected but not even achieved, and B is even less likely.
どころか can also mean 'on the contrary', so context is important. It often implies the first item is not true, unlike はもちろん.
彼は謝るどころか、逆に怒り出した。
Far from apologizing, he got angry — to say nothing of apologizing.
A formal, often written pattern meaning 'let alone A, even B'. Used to emphasize that B is also true or not true, with A being the more obvious case.
彼は海外旅行はおろか、国内旅行もしたことがない。
He has never traveled domestically, to say nothing of overseas.
はもちろん is the most common and neutral. はもとより is formal/written. はおろか is formal and often used in negative sentences to emphasize that even a lesser thing is not true. どころか is different: it often negates the first item and adds a stronger contrasting point.
彼は漢字はもちろん、ひらがなも読めない。
He can't read hiragana, to say nothing of kanji.
彼は漢字はおろか、ひらがなも読めない。
He can't read hiragana, let alone kanji.
Do not translate 'to say nothing of' literally as 何も言わない (say nothing). It is an idiomatic phrase meaning 'not to mention' or 'let alone'.
彼は車はもちろん、家も買えない。
He can't afford a car, to say nothing of a house.
彼女は数学はもちろん、理科も得意だ。
She is good at math, to say nothing of science.