れる・られる (Potential)To be able, Can (Potential)

In addition to 'passive' verbs, れる and られる (the auxiliary verbs) are used when expressing possibility '可能(かのう)'.

られる will be attached to the base form of る-Verbs (the form after る has been removed). Note also that れる and られる themselves behave like standard る-Verbs, so can be conjugated into a variety of different tenses in the same way as a standard verb.

A common sight in modern Japanese is words where the ら may be removed, 'ラ抜(ぬ)き言葉(ことば)', and れる may be used by itself. However, this is not technically correct Japanese, and may cause confusion in cases where ら is required (with る-Verbs and くる, when られる is expressing 'passivity', 'respect', or 'spontaneous occurrence').

For う-Verbs, they will behave a little differently. Instead of the final kana of the verb changing to an あ sound, and then adding れる (as would be the case with passive verbs), the final kana of the verb will change to an え sound (る will become れ, う will become え, す will become せ, etc.) before adding る.

Interestingly, する verbs do not have a 'potential' form, and the verb できる will be used in its place.