Duo, please go to Duo French to observe how French pronunciation words is practiced (in the French case, of diphthongs) and apply this to the 44 different Hungarian pronunciations. Until the ear hears correctly, the language is not properly learned. Practice, practice, practice the connection between the written character and the sound. That! makes perfect for language learning!
There's certainly a difference, but it's not visible when the subject is in the 3rd person (e.g. he, she, it, this, the car, your mom, etc.). 'Ez' simply means 'this' (though these words have two different uses in each language). It's translated as 'this is' on Duolingo simply to demonstrate that 'van' is not used in Hungarian when saying that "A = B", when A and B are both nouns.