Changing Username caption on the front of the site

The login window on the Homepage has the caption for Username and Password. I'd like to change the one for Username to E-mail since I customized my dolphin to only login using the e-mail address.

Find and replace  that phrase in admin -> settings -> language settings

 I tried that already. I searched for Username in language keys, and a bunch of keys came up. I tried changing each one and testing it out, neither worked.

I searched for "Username". I also tried "Username:" and it did not come up at all. I would think that the second one is correct since on the front of the website, there is a colon just after the word.

 there are approximately 21 iterations of Username in the database under sys_localization_strings

 and searching on admin panel reveals about the same count:

_E-mail or ID (System) Edit

So I guess that means I have to clear cache and verify again every single one.

Thanks. I'll give that a try.

well you can do that, or grep for the langkeys, since i ran grep for "Username" and nothing came up, so that tells me its resolving to a langkey in the source.

so you would look at the instances here in the list that are depicted with _

and most likely the source is going to call on the langkey rather than the word Username:

 That worked!

Thank you.

I am also looking for the answer to this question. Please could you post how you found the language key to 'USERNAME'. I don't know how to use grep!  Also the answer would be helpful!