Are 新しい and 新たに etymologically related?


The words 新しい{あたらしい} and 新た{あらた}に sound very similar to me, but I wonder
whether they are really related. If so the root must have undergone metathesis
(switching the order of sounds). Are they actually etymologically related?

Note: I saw [this
question](https://japanese.stackexchange.com/questions/4769/when-would-you-
use-%E6%96%B0%E3%81%82%E3%82%89%E3%81%9F%E3%81%AA-
and-%E6%96%B0%E3%81%82%E3%81%9F%E3%82%89%E3%81%97%E3%81%84) but I'm asking
about etymology rather than usage. (Though there does happen to be some
relevant information in the answer there.)




One theory is indeed that 新しい derives from あらたし via metathesis as あらたし in the
beginning of the Heian period became あたらし and then あたらしい.

[語源由来辞典](http://gogen-allguide.com/a/atarashii.html) lists another theory:
あらたし (meaning "new") was confused with the already existing あたらし meaning 惜しい.
あたらし was used with the meaning "new" and the other meaning of 惜しい fell largely
out of use.

In any case, 新しい and 新た are etymologically related.




One theory is indeed that 新しい derives from あらたし via metathesis as あらたし in the
beginning of the Heian period became あたらし and then あたらしい.

[語源由来辞典](http://gogen-allguide.com/a/atarashii.html) lists another theory:
あらたし (meaning "new") was confused with the already existing あたらし meaning 惜しい.
あたらし was used with the meaning "new" and the other meaning of 惜しい fell largely
out of use.

In any case, 新しい and 新た are etymologically related.

