Consonants of Hangul

King
Sejong and his scholars created consonant symbols of Hangul from the shape
of the tongue when you pronounce them. Not all of them were based on tongue
shape. There were sort of 'basic' symbols which were created from tongue
shape. The rest of the consonant symbols were made by adding short lines
to the basic symbols. The symbol for voiced velar stop, which roughly corresponds
to English /g/, is shown at the upper left corner of the second picture.
If you see the symbol at the upper right corner of the first picture (the
one beside the blank), you will know that they are very much alike, except
the short horizotal line. The one with an extra line represents aspirated
and thus voiceless counterpart of the velar stop. If you put two of the
voiced velar stop sucessively, the symbol stands for the unaspirated voiceless
(or someone might say voiced) velar stop. In short, sounds with the same
place of articulation have much in common in their symbols.
As you saw above, Hangul symbols are not just arbitrary combination of
sounds and symbols. They ARE arbitrary symbols in the sense that you cannot
know how to pronounce those symbols from their shapes alone, but some of
them can be grouped together just as we classify consonants into their
place of articulation and manner of articulation. In figure 2, you see
those two voiced and voiceless velar stops grouped under velar stop section
with a symbol for unaspirated velar stop between them. If you look around
a little, you can find some other basic symbols and their modified forms.
In the alveolar stop section, the rightmost letter is the basic form of
voiced stop. The leftmost symbol of the section corresponds to the voiceless
alveolar stop and the symbol in between, as you have guessed by now, is
for the unaspirated stop.
English
alphabetic letters for voiceless and voiced bilabial stops are 'p' and
'b'. They don't have much in common in their shape though some might say
they do. Then take 't' and 'd' for example. Do they look alike? Probably
no. But if you take a look at the alveolar stop section, the leftmost and
rightmost symbols do look alike except just one short line added to one
of them. It's roughly the same with other stop sections in the sense that,
in each section, one of them is the basic type and that the others are
somewhat derived forms. It's a lot easier to memorize things related with
each other in one way or another than to memorize many, totally different
things. That must have been what the king and his scholars thought. Because,
as his explanation indicates, Hangul was for ordinary people in those days.