Translation guide
Used to add a stronger or more obvious point to an argument. In Japanese, this is expressed with sentence-ending particles, conjunctions, or set phrases that emphasize the preceding statement and imply 'and of course...' or 'let alone...'.
The speaker states something, then adds a more extreme or obvious related point, meaning 'and certainly also...' or 'not to mention...'.
A common pattern meaning 'not to mention A, also B'. 'Aはもちろん' literally 'A is a matter of course', followed by 'Bも' (B also). Used in both spoken and written Japanese.
He can speak French, not to mention English.
This restaurant has great service, not to mention the taste.
More formal/literary than 'Aはもちろん'. '言うまでもなく' means 'it goes without saying'. Suitable for writing or formal speech.
His personality is respected, not to mention his achievements.
Emphatic pattern meaning 'far from A, even B'. Often used when B is more extreme than A. Can imply 'not to mention' in a stronger, sometimes negative sense.
He got angry, not to mention apologizing.
Used to say that something is so far from being possible that even a lesser thing is impossible. 'He can't even walk, let alone run.'
Formal/literary pattern meaning 'let alone A, not even B'. Used with negative predicates. 'Aはおろか' emphasizes that A is out of the question.
He can't even walk, let alone run.
I've never even traveled domestically, let alone abroad.
Similar to 'Aはおろか' but more common in spoken Japanese. Emphatically denies both A and B.
He can't even speak Japanese properly, let alone English.
Adverb meaning 'much less; let alone'. Used at the beginning of a clause. Often in formal or literary contexts.
Adding an extra piece of information as an afterthought, similar to 'and also...' or 'not to mention...' in casual speech.
'Aはもちろん' is used for positive additions ('not to mention A, also B'). 'Aはおろか' is used in negative contexts ('let alone A, not even B'). Mixing them up can change the meaning drastically.
He speaks French, not to mention English. (positive)
He can't speak French, let alone English. (negative)
There is no direct word-for-word translation of 'not to mention'. Using '言及しない' (mention) would be unnatural. Instead, use the patterns above that fit the context.
彼は簡単な計算もできない。ましてや複雑な数学は無理だ。
He can't do simple calculations, let alone complex math.
It started raining, not to mention the wind is strong.