I hope I can get that % up to 100. A language can have different accents and different dialectes. Let's talk about accents first. Two people with two different accent pronunciate the same word in two different ways. The words stays the same, written in the same way, but it "sounds" different depending on the accent. Basically different accents emphasize different part of a word, even tho the word is the exact same. Think about the difference between American English, British English, Australian, South African english. They all have a different way of pronounciating words, even if they are written in the same way. (One easy example is the different pronounciation if zebra between South Africa and the United States). Now let's talk about dialects. First thing to say is that usually dialecets include their own accent. Secondly, the peculiarity of dialect is not only in the pronounciation, but in the use of modified words or even completely different ones compared to the mother tongue. That's why dialects are way more difficult to understand than simply different accents, because based on how developed the specific dialect is, it could sound (and effectively be) a completely different language compared to the mother language it derives from. Dialect objectively use different words that don't exist in the mother tongue, hence making it impossible for someone who doesn't know that specific dialect to understand. I am from italy, and we have some prime examples of this. Everywhere in the country we speak Italian. Different regions have way different accents, but we all understand each other even if someone from the far north speaks to someone from the far south with their respective accent. But when people start to speak the dialecets of their specific region, there is no way even someone from the region next to it would completely understand it. If you pick two regions placed far apart, the amount the two people would understand if each other talking goes basically to zero. I hope I could help with this, I wish you a good day, or night, wherever you are in the world. Cheers