What is the difference between the two words
I think for
こぼれる, the focus is on improper or bad containment leading to overflow/spillage.
あふれる the focus is on the abundance of the object being contained, therefore leading to overflow/spillage.
As an aside, how frequently is the kanji
溢 used for
I ask this because Google IME suggests
溢れる for both
あふれる usually in kana and