It is famous for ら抜き言葉(the words without 'ra')

We Japanese often say it as "食べれる".

Grammatically it is incorrect. But these days, this wrong phrase have been involved

in our minds and people have got to accept it.

So I've tried to use it as a formal way. like "食べられる"

A Japenese professor said that it is natural for us to change the form.

We don't want to use energy to say the language.

「られる」has two meaning : one is possibility(like 'can') ; another is passive.(be -ed)

  I can recognize the "られる” as two meanings.

  That's why some people can feel the meaning "食べられる” as a passive form.

　例

  　カエルが蛇に食べられた。（蛇がカエルを食べた。）

　　私は納豆を食べられた。（私は納豆を食べることができた。）