Mail vs. Email

Here is an interesting grammatical fact about the nouns mail and email. In English, mail is an uncountable noun (see here), which means that

Send me a mail

is not grammatical. However, even though email (or E-mail) is a short form of electronic mail, it can be both countable and uncountable (see here). Hence,

Send me an email

and

I did not receive email today

are both correct. Similarly, we have

He sent me two mails. (Incorrect)
He sent me two emails. (Correct)

To make things worse, in German, both Mail and E-Mail can be countable or uncountable, see here. Hence, is is grammatical to say

Schick mir eine Mail.