Hangul is the only phonetic writing system in the world, which was deliberately invented to transcribe any sound in the nature, including human languages. It was invented by King Sejong and eight court scholars in 1443, after toiling more than half a dozen years of study in phonetics. It is known as one of the most scientific writing systems in the world.
How scientific it is can be summarized by following.
Basic consonants are: ㅇ(o), ㄱ(g), ㄴ(n), ㅅ(s), ㅁ(m).
These basic consonants are symbols of the organs of where the sounds are created.
ㅇ is the symbol of round throat.
ㄱ is the symbol of lifted tongue root.
ㄴ is the symbol of tongue tip lifted.
ㅅ is the symbol of sharp teeth.
ㅁ is the symbol of closed lips.
On these basic alphabet, added a bar to make it an aspirated sound (an example is ㅈ(pronounced J, in case of John), which has a bar on the top of ㅅ. Added a dot on the top of this ㅈ, to make a harsh sound ㅊ (pronounced CH, as in the case of Children).
These basic consonants have different note scales according to the distances from the voice box located deep in the throat. It was modeled after the flutes of 15th Century with five holes with five different musical notes and its frequency matches with five basic consonants.

Basic vowels are:
‘.’ Symbol of heavenly SUN, (pronounced as AU, in the case of August)
‘ㅡ’ Symbol of flat EARTH, (there is no matching pronunciation in English,
however, similar to EAU, in the case of Beaumont)
‘ㅣ’ Symbol of upright MAN, (pronounced as EE, in the case of Eel)

Combining these three symbols, it can create:
ㅏ(pronounced A, as in the case of Arm)
ㅑ(pronounced YA, as in the case of Yahoo)
ㅓ(pronounced EO, as is the case of Seoul)
ㅕ(pronounced YEO, as in the case of Young)
ㅗ(pronounced O, as in the case of Ohio)
ㅛ (pronounced YO, as in the case of Yoyo)
ㅜ (pronounced WOO, as in the case of Wood)
ㅠ (pronounced YOU, as in the case of You)

More consonants and vowels can be created by combining with two or three together.

These combined alphabets (double or triple) can create millions of syllabic characters. For example:
ㄱ(g) + ㅏ(a) = 가 (ga). Since each Hangul alphabet has only one sound value (pronunciation), it is easy to pronounce combined syllabic character.
More example are: ㅅ(s) + ㅗ(o) + ㄴ(n) = 손 (son), meaning hand.
ㅂ(b) + ㅏ(a) + ㄹ (l) = 발 (bal), meaning foot.
ㅋ (k) + ㅗ (o) = 코 (ko), meaning nose.
ㄴ (n) + ㅜ(oo) + ㄴ(n) = 눈(noon), meaning eye.

Hangul is so easy that ordinary person can read and write within a few hours of practice.
Phonetic Hangul keyboard was designed to teach people how the phonetics of any language in the world can be easily learnt.