It just takes practice, I guess? I often have problems with that too, it really isn't easy to distinguish the two sounds if you're not used to them. But they can't accept 'y' in place of 'e' and vice versa, because there is a difference between them, even if we can't hear it so well yet. And it's an important difference too, just think about adjective declension.
Ah! It got me! Technically, writing, that is.... This sentence was counted wrong because I didn’t capitalize the first word. https://www.dropbox.com/s/lnw1p5f1o8vew6m/Photo%20Sep%2021%2C%206%2000%2044%20PM%20%281%29.png?dl=0