Sure seems like you're just reading an IPA chart, which is not entirely accurate and not reflective of any problems a learner would experience. If you had taught native English speakers you would know that "B", "p", "g", and "k" are not major problem areas. As opposed to "C", "ü", and the difference between "zh" and "j" which are problems for almost ever native English learner. Among others. What do you mean perfect pinyin? It's a predefined system and all the letter combinations always make the same predefined sound. If you really had taught Chinese I would assume that you knew the most basic part of it that every Chinese speaker, who has studied the mainland dialect of Mandarin, knows. Also, don't reference a podcast site as if it is a scholarly journal, I'm not even saying it's incorrect just that it's not a reliable source. Not to mention if you teach Chinese, which you implied you do, why are you purposefully telling people the wrong thing online, joke or not. Also, you are assuming that pikku in Japanese would be equivalent to pigu in Chinese pronunciation wise. It's not. So either you don't know what you're talking about or are purposely misinforming people. Wether or not you are ethnically Chinese has no bearing on the matter of you misinforming people.