When I was a child my mom told me that drinking juice with milk together would upset my stomach like nothing else, like vomiting guaranteed. So, of course, the next chance I got I just had to try this out, just to see for myself if she was right. And while it stayed in my stomach, it sure as hell was the most vile thing I drank.
Тут є одна відмінність. And тут може перекладатися на українську, як "і" так і "та". Але це зовсім не свідчить про те, що молоко змішане з соком. Якщо б воні були змішані, то був би використаний інший прийменник - "з". У випадку "ви п’єте молоко (разом) з соком" - вже зрозуміло, що вони змішані.
The apostrophe shows that the p isn't affected, or "palatalized" by the following ioticized vowel. I'm not sure what the affect of palatalization, if any, would be in this case, but it's the same thing that happens when the 'jer' character comes after a consonant like in 'uncle'/'djad(zh)ko'.
The ' (apostrophe) is the hard sign in Ukrainian. As you indicated, the preceeding vowel is not softened, and the following vowel is fully palatalized (ioticized). The best way to visualize this process is to say the п fully before the є; in other words, don't run them together as if they are a dipthong, as is often done in English. For example, in English the word 'please' is sometimes pronounced p-leeze when someone wants to emphasize it. The p is pronounced separately to the l. In normal use, the p and l are said as one sound.