Checks if all of the characters in the provided string,
text, are alphabetic.
In the standard C locale letters are just
[A-Za-z] and ctype_alpha() is
equivalent to (ctype_upper($text) || ctype_lower($text))
if $text is just a single character, but other languages have letters that
are considered neither upper nor lower case.
Returns TRUE if every character in
a letter from the current locale, FALSE otherwise.
Example 1. A ctype_alpha() example (using the default locale)
The above example will output: