Are "at all" and "whatsoever" always interchangeable in negative and interrogative sentences? Make sure to use quotation marks in English as the sentence is much harder to understand without them. ) In short: yes. A bit of their nuance explained: First, you need to include the word "any/a/an" before the subject. Both phrases are emphatic, meaning they express a greater deal of emotion. If you use them in a question, it could potentially become offensive by adding either phrase. "Do you speak Russian?" Do you speak this language? simple, direct. Ты говоришь по-русски? "Do you speak *any* Russian at all?" can you speak even one word of this language? "Do you speak *any* Russian whatsoever?" can you speak even one word of this language? К сожалению, мне не ясно, как говорится на русском, но здесь нам (носители английского) хотелось бы выразить недоверие или недоумение с помощью этих фраз. However, it would be polite if someone says "I had Russian parents" and you asked them, "Oh, do you speak any Russian?" and they might respond, "Sadly, I don't speak any Russian whatsoever." Whereas, you can use them freely when describing yourself and it underlines that you are very unfamiliar with a subject. I don't speak any French whatsoever/at all. Я даже ни слова не говорю по-французски I don't know anything whatsoever about this subject. Я вообще ничего не знаю касательно этого предмета. Hope that helps a little bit )))