What is the significance of a repeated radical in a Kanji character?


What is the significance (if any) of a repeated radical in a Kanji character?

I have been learning Kanji for almost a year now. In the early days my
assumption would have been that repeating a radical would emphasise
quantity/intensity/scale in an intuitive way such as with the following
characters:

> # 木 林 森

Now I am starting to come across Kanji with repeated radicals where the
meaning (at least to me) isn't as obvious. I notice they almost always appear
as adjacent pairs.

> # 談 態 曜 歌




In general, don't overinterpret repeated components. It's inconsistent and
largely a hit-and-miss exercise.

Sometimes they just mean "lots of" the single repeated component, or some
extended meaning from that. For example, in addition to 「木」->「林」->「森」, there
is

  * 「火」( _fire_ ) ->「炎」( _blaze_ )
  * 「屮」( _sprouting plant_ , not used as an individual character) ->「艸」(full character form of 艹, _grass radical_ )
  * 「人」( _person_ ) ->「衆」( _crowd_ ; the bottom was actually originally 3「人」, as can be seen in the Taiwan variant「眾」)
  * 「」( _right hand_ , top left component of「右」) ->「友」( _friend_ , two right hands) 
    * Note that「又」was also originally a picture of a right hand; the meaning _again/also_ is a phonetic loan, and had nothing to do with the character itself.)
  * 「一」->「二」->「三」(trivial example)
  * There are also plenty of Chinese-only examples that I won't mention here.

Other times, they don't have anything in particular to do with the whole
character, like all the rest of your examples.

  * 「[談]{だん}」is just a word meaning _to discuss_ that has a semantic component「言」and a phonetic component「[炎]{えん}」. 
    * There was an ancient variant「譚」that meant and was pronounced exactly the same as「談」; neither「譚」nor「談」, nor other characters which use「炎」as a phonetic component, such as「[淡]{だん}」( _dilute_ ) or「[毯]{たん}」( _carpet_ ), have anything to do with _fire_.
  * 「[態]{た​い}」( _manner_ ; c.f. [態度]{た​いど}, _attitude_ ) has a semantic component「心」and a phonetic component「能」, which had a very ancient alternative pronunciation of「ない」. 
    * The repeated component「匕」doesn't actually contribute to the meaning of「能」at all, because「能」( _ability_ ) was originally a phonetic loan, and cannot be broken down; the original character was a full-fledged picture of a type of bear, where「匕」was the bear's legs:  
[![enter image description
here](https://i.stack.imgur.com/N6bZV.png)](https://i.stack.imgur.com/N6bZV.png)

    * _Bear_ is now written「熊」to differentiate the character from the meaning of _ability_.
  * 「曜」just has a semantic component「日」and a phonetic component「翟」. 
    * 「翟」had an Old Chinese pronunciation ***lˤewk** , while for「曜」, The pronunciation evolved in accordance to **/*lewk-s/** (Old Chinese) -> **/jiᴇuʰ/** (Middle Chinese) -> **よう** (Japanese On'yomi).
    * The repeated component「习」cannot be separated from「羽」, which was originally a picture of _feathers_.
    * 「翟」originally referred to a type of bird:  
[![enter image description
here](https://i.stack.imgur.com/OA8k9.png)](https://i.stack.imgur.com/OA8k9.png)

  * 「[歌]{か}」just has a semantic component「欠」and phonetic component「[哥]{か}」. 
    * 「欠」was originally a depiction of a person with an open mouth:  
[![enter image description
here](https://i.stack.imgur.com/Z8qJI.png)](https://i.stack.imgur.com/Z8qJI.png)  
The meaning _to lack_ is an extension from the original meaning. Other
characters which feature「欠」as a semantic component include 吹 ( _to blow_ ) and
歎 ( _to sigh_ , variant of 嘆).

    * 「哥」itself is an ancient variant of「歌」and is no longer used for the meaning _song_. It is a reduplication of「[可]{か}」, which also originally meant _song_ , but very early on shed this meaning and took on the role of a phonetic loan for _can, be able to, permissible_. These original meanings of「哥」and「可」were entirely lost through the course of history, and you shouldn't view「哥」as "lots of 可".




In general, don't overinterpret repeated components. It's inconsistent and
largely a hit-and-miss exercise.

Sometimes they just mean "lots of" the single repeated component, or some
extended meaning from that. For example, in addition to 「木」->「林」->「森」, there
is

  * 「火」( _fire_ ) ->「炎」( _blaze_ )
  * 「屮」( _sprouting plant_ , not used as an individual character) ->「艸」(full character form of 艹, _grass radical_ )
  * 「人」( _person_ ) ->「衆」( _crowd_ ; the bottom was actually originally 3「人」, as can be seen in the Taiwan variant「眾」)
  * 「」( _right hand_ , top left component of「右」) ->「友」( _friend_ , two right hands) 
    * Note that「又」was also originally a picture of a right hand; the meaning _again/also_ is a phonetic loan, and had nothing to do with the character itself.)
  * 「一」->「二」->「三」(trivial example)
  * There are also plenty of Chinese-only examples that I won't mention here.

Other times, they don't have anything in particular to do with the whole
character, like all the rest of your examples.

  * 「[談]{だん}」is just a word meaning _to discuss_ that has a semantic component「言」and a phonetic component「[炎]{えん}」. 
    * There was an ancient variant「譚」that meant and was pronounced exactly the same as「談」; neither「譚」nor「談」, nor other characters which use「炎」as a phonetic component, such as「[淡]{だん}」( _dilute_ ) or「[毯]{たん}」( _carpet_ ), have anything to do with _fire_.
  * 「[態]{た​い}」( _manner_ ; c.f. [態度]{た​いど}, _attitude_ ) has a semantic component「心」and a phonetic component「能」, which had a very ancient alternative pronunciation of「ない」. 
    * The repeated component「匕」doesn't actually contribute to the meaning of「能」at all, because「能」( _ability_ ) was originally a phonetic loan, and cannot be broken down; the original character was a full-fledged picture of a type of bear, where「匕」was the bear's legs:  
[![enter image description
here](https://i.stack.imgur.com/N6bZV.png)](https://i.stack.imgur.com/N6bZV.png)

    * _Bear_ is now written「熊」to differentiate the character from the meaning of _ability_.
  * 「曜」just has a semantic component「日」and a phonetic component「翟」. 
    * 「翟」had an Old Chinese pronunciation ***lˤewk** , while for「曜」, The pronunciation evolved in accordance to **/*lewk-s/** (Old Chinese) -> **/jiᴇuʰ/** (Middle Chinese) -> **よう** (Japanese On'yomi).
    * The repeated component「习」cannot be separated from「羽」, which was originally a picture of _feathers_.
    * 「翟」originally referred to a type of bird:  
[![enter image description
here](https://i.stack.imgur.com/OA8k9.png)](https://i.stack.imgur.com/OA8k9.png)

  * 「[歌]{か}」just has a semantic component「欠」and phonetic component「[哥]{か}」. 
    * 「欠」was originally a depiction of a person with an open mouth:  
[![enter image description
here](https://i.stack.imgur.com/Z8qJI.png)](https://i.stack.imgur.com/Z8qJI.png)  
The meaning _to lack_ is an extension from the original meaning. Other
characters which feature「欠」as a semantic component include 吹 ( _to blow_ ) and
歎 ( _to sigh_ , variant of 嘆).

    * 「哥」itself is an ancient variant of「歌」and is no longer used for the meaning _song_. It is a reduplication of「[可]{か}」, which also originally meant _song_ , but very early on shed this meaning and took on the role of a phonetic loan for _can, be able to, permissible_. These original meanings of「哥」and「可」were entirely lost through the course of history, and you shouldn't view「哥」as "lots of 可".

