Some further comments from a Korean speaker and Seoul resident:
Korean certainly does not used a mixed alphabet/chinese character system as someone above mentioned.
In the past in newspapers and official documents you would see some chinese characters but these days even the major newspapers rarely use them except in very specific circumstances and there are some major dailies who never use them. Further, Korean chinese characters are called Han-ja.
Some notable exceptions to the chinese character rule: Calenders still have the characters for the days of the week. Most Koreans can write their name with chinese characters because thats where parents take their children’s names from. So most Koreans have a specific meaning behind their name like, “Lavender Wind” or “Strength and Diligence”. All Korean family names, of which there are only about 74 in total, have a corresponding chinese character. For example, the most popular family name “Kim” is the character for “gold” (geum). Most koreans have a three-syllable name. One syllable for the family name (Kim, Lee, Park, Jung, Oh, Shin etc) and a two syllable first name(Jung-min, Mee-sun, Yu-jin etc), where each syllable is derived from a chinese character. However some people only have a single syllable first name and in some rare cases three syllables.
However, with that said, it is becoming increasingly popular with new parents these days to forgo giving their children a name derived from two chinese characters and give them a korean only name. For example, a popular new girl’s name is “Ha-Neul” which literally means Sky and others like “Seul-bi” which have no intrinsic meaning whatsoever.
As for the discussion of hangeul itself, many Koreans will tell you its the perfect system but it has some flaws. Although it is easy to learn the basics there are a lot of nuances one has to work out. There are a lot of instances of collision effects of consonants and consonants also change their sound depending on their position.
For instance the sieot (ㅅ) which is an “s” if it is the first consonant, changes to a soft “t” if it is the terminating consonant or “pachim”… but if that terminating sieot is immediately followed by a vowel then it maintains its original phonetic value of an “s”. Furthermore, if the sieot (s) is followed by the “ee” vowel, then the “s” becomes an “sh” and pronounced as in “she”. There are a lot more other examples involving other consonants and vowels that break the simple rules.
The voiced unaspirated consonants (ss, jj, kk, bb, dd) in Korean are extremely difficult for a native english speaker to not only hear but also voice. To most it usually sounds like the same as regular consonant, just louder.