Hearing difference between 那里 and 哪里

Question

Of course it is the fate of any native speaker of English to struggle with tones. And I suppose I should be happy I have begun with Mandarin, which is far less extravagant in its tone system than are many other languages. But one place I feel hopeless is in distinguishing between 那里 and 哪里. I know that 那 is fourth tone and 哪 is third tone, but that knowledge isn’t helping me hear the difference.

I’ve been using Duolingo (maybe that’s my problem?) but when these words are used in any context (so not in isolation) and spoken at anything above glacial speed, I fail to notice a difference. Luckily, one often knows from context which is meant. But other times not. For instance, I find it nearly impossible to distinguish whether someone is saying “我的手机在那里” or asking “我的手机在哪里?”

Does anyone have any advice on how to sensitize one’s ear? The same question applies for 那儿 and 哪儿, though sometimes I hear (Duolingo producing) 哪儿 as rhyming with English fair, while 那儿 rhymes with far.

Answer 1

那nà starts at a high pitch and then falls down. 哪nǎ starts at a relatively low pitch, and then goes down and up a little bit.

Plus, the statement that “Q: 她去那/哪里了? - In this case, 那里 = 哪里, [nǎ lǐ], both sound the same and mean the same, "where"” is definitely not true. 她去那里了？：Did she go there? 她去哪里了？：Where did she go? If one types “那里” and means to say “where”, then it must be a typo. It’s a common typo for native speakers to make on the internet, but we know the difference pretty well irl.

Answer 2

This is very common in non-native Chinese learners, and it's usually because of the inadequate experience of speaking and listening to them. Sometimes, in daily contact, we ourselves will also mistake one for another. People have different pitches in speaking, plus the mood when we're speaking, distinguishing between them is not only about your ears but also your brain to investigate the context and give a result of the highest probability.

In the most standard Mandarin pronunciation (標準官話), the four pitches can be distinguished very well from each other. However, the pronunciation in Duolingo and the daily conversation between the Chinese often reduce the differences between the pitches, making it harder to be told apart.

And at the end, as I've said in the comments, Duolingo uses AI to pronounce the words in the courses. And so, there are pronunciation mistakes or unnatural pronunciation when they are pronounced quickly. This is especially obvious in the pronunciation of Asian languages ​​such as Japanese and Cantonese (which I've actually tested). So do not bother with the hearing in it. If you want to practice your hearing, I recommend those on YouTube or anywhere else with human pronunciation.