안녕하세요 – An-nyeong-ha-se-yo. – Hello.
Although straightforward, this expression is a necessary inclusion and is without doubt the most common phrase anyone in Korea will use. There are dozens of variations to account for slightly different situations and levels of respect, which can get fairly complicated for the non-Korean speaker. The trick is to say it quickly and slur the syllables together. Do this and everyone will understand you.