In kanji 外, why is タ used instead of ソ?


Why is タ used instead of ソ in 外 despite it's read as ソト?




As you may or may not be aware, Japanese employs three writing systems:
Hiragana, Katakana, and Kanji.

Hiragana and Katakana, collectively called Kana, are phonetic writing systems
that were developed and modeled after Kanji. Hiragana came about from a
modification of cursive script of certain Kanji, whereas Katakana are pieces
of these Kanji, repurposed and ascribed with a phonetic value.

Kanji, however, are essentially ideographs, meaning that they represent an
idea, and not a sound. While Katakana may have been derived from pieces of
Kanji, it unfortunately does not work the other way -- It doesn't make much
sense to put Katakana together to form a Kanji and expect it to be read a
specific phonetic way, unlike how Korean works by making symbols from the
combination of pieces.

For this reason, observe that even though the Kanji 外 appears to be composed
of Katakana タ and Katakana ト, it is actually not made of either of these. It
is not read タト(tato) and thus replacing タ for ソ would not be correct because
we shouldn't be trying to modify the written character so that it matches a
reading it has. That's because 外 can be read in other ways, as well. Consider
these words in which it appears:

> 外{そと}  
>  外国{がいこく}  
>  外{はず}す

If we were to try to use that logic to figure out how to read other Kanji, how
would we read something like 青 or 終?

Then, we have to consider that the Kanji 外 is essentially one contiguous
symbol that has a meaning, not a sound. I suggest you read more about how
Kanji are put together, and how radicals work, before continuing to use them.

