While it is certainly true that in spoken Korean, there are never two consecutive consonants in the same syllable; It should be noted that this is not true of written Korean, called Hangul. Many Korean syllables have two consecutive consonants. Some even have two sets of double consonants. There are two cases in which this occurs:
1. The korean verb "to read" is spelled with four letters arranged in one syllable. The mute consonant to indicate the syllable starts with a vowel sound, the vowel "i" (pronounced as a long 'e'), the consonant "r/l", and the consonant "k/g".
When the verb is in its dictionary form, it is followed by the syllable "da." In this case, the "k/g" sound is dropped and the verb is pronounced approximately like "ir-da". However, in certain cases, such as past tense (verb + "ot" pronounced as 'oat') the verb is followed by a vowel, in which case, the "k/g" sound is brought back as part of the following syllable "ir-kot".
2. The verb "to use" is spelled with three letters. Two of the consonant "s" and the vowel "eu" (sounds like the grunt made by getting hit in the stomach). The result is a slightly sharper pronunciation of the "s" consonant "sseu."