Korean pronunciation is vastly different from English, and it takes a lot of practice to be able to be able to pronounce words correctly.
One of the major mistakes English speakers make is to assume that the pronunciation of Romanized Korean letters is identical to the same letter's pronunciation when speaking English. Unfortunately for language learners, this is not the case. Beginners will have to relearn the correct Korean pronunciation of Romanized letters.
In English, whenever a word ends in a consonant, the speaker always makes a little sound after saying that last letter. It is very faint and difficult to hear for a person with a ‘non-Korean ear’ to hear. For example, when an English speaker says “ship” there is a tiny sound of breath following the ‘p’ when their mouth opens. In Korean, they do not have that final ‘breath’ sound, as they just keep their mouths closed.