Pronunciation Difference: English vs Korean

Most Koreans spend a lot of time and money to learn English; however, they say it is too difficult to learn English. What makes them feel learning English is so hard? There are many reasons: different language family, pronunciation, alphabet system, grammar and so on. These can be one of the main reasons why Koreans take more time to learn English than Europeans for example. Korean English learners have more difficulty when they speak in English even though they can read and write. Pronunciation difficulty is a big problem when Koreans speak in English. Thus I would like to compare the pronunciation differences between the two languages.
First of all, I would like to compare phonology of the two languages. Korean is a syllable-timed-language in which individual word stress is insignificant. This is radically different from English which is a stress-timed language. This is why Koreans produce the 'flat' quality of much of the English whey they speak. Differences in syllable structure between the two languages may lead to the addition of a short vowel sound to the end of English words that terminate with a consonant or within words containing consonant clusters.
The next significant problem in pronunciation is consonants. Several English consonant sounds do not exist in Korean. They are the /θ/ and /ð/ sounds in words such as then, thirteen and clothes, the /v/ sound, which is produced as a /b/, and the /f/ sound which leads, for example, to phone being pronounced pone.
There are a lot of differences between English and Korean which make it harder most Korean learners to master English. The pronunciation difference can cause miscommunication between speakers and listeners. Thus English teachers should teach the differences for their better pronunciation. It may result for Korean English learners to feel more confident when they speak.