English Speakers Are Going to Have Trouble With the Plain and the Voiced Uh

When you get a three-way distinction English speakers are going to have trouble with the the plain and then the voiced. The voicing is missing the velar and the palatal africate so that's not in any way unusual. In terms of vowels that's where things start to get really interestingYeah it's a symmetrical seven vowel system with two un round or two um unrounded back vowels right?