They're actually pronounced differently, it's just a variation in pronunciation that isn't typically used to distinguish meaning in English. Think of when you say a statement vs asking a question in English, for example. That's a rising tone, and while in English it doesn't change the meaning of a word but indicates a question, in tonal languages it can change the actual meaning.
It is hard for English speakers to pick up as it just isn't something that is found in English, but if you get the tones wrong what you say is just incomprehensible. It sounds the same to you, but even when they figure it out and correct you, what they say back sounds exactly like what you said! Most of my experience being corrected is with tonal languages other than Chinese such as Thai, though, as very often unless you can speak Chinese serviceably they really just don't bother trying to communicate with you in the first place.
It doesn't help that Chinese aren't particularly patient with foreigners trying to speak their language and can be downright deliberately stupid in interactions with them, possibly because they are just stressed by the interaction... China is one of the very few countries I have been where very commonly they really really just don't make the slightest effort at communication- you can be in a hotel and in any other country you would think it is probably pretty obvious what someone standing in a hotel lobby miming sleeping is looking for, but in China they will just look at you blankly. Same with asking a shopkeeper or stallholder if they have something, if they don't have it they will just say "meiyou" (do not have) while waving their hand in front of their face. It absolutely doesn't matter that the stall immediately beside them has exactly what you are looking for, it's just meiyou and the wave hand thing. Sometimes they even DO have it, they just don't want to interact with a foreigner.
Buying train tickets was another great experience, six other people in the hostel I was in in Guanzhou tried to do this and failed, some of them just gave up and used a travel agent, others ended up booking flights instead because they could do that online. So I was prepared going to the train station and had the hostel people write down the name of the city I was going to, the date I wanted to go and the class I wanted to travel in. Queue for an hour until I get to the ticket desk, and show my paper. Meiyou, with the hand waving. I took my paper back and wrote down the next day. Meiyou. I made it clear that I was perfectly willing to stay here all day swapping this bit of paper back and forth and I wasn't going anywhere until I got a train ticket for Chengdu, so after swapping this back about four times with different variables changed she finally relented and managed to convey that there was a berth in second rather than third class two days from when I wanted to travel...
This is honestly a real Chinese thing, for some reason, I have been in Asia five years now and have never had a major issue communicating basic needs like a bed or food anywhere else, but Chinese in service positions for some reason really seemed just not to want to deal with foreigners. Great country and great people in the main all the same, I also got the celebrity treatment with them wanting to take photos and lots of drinks and meals bought for me, it's just a strange peculiarity they have.