The word “uncopyrightable” is the longest English word in normal use that contains no letter more than once.
A sentence that contains all 26 letters of the alphabet is called a “pangram”.
The following sentence contains all 26 letters of the alphabet: “The quick brown fox jumps over the lazy dog.” This sentence is often used to test typewriters or keyboards.
The only word in English that ends with the letters “-mt” is “dreamt” (which is a variant spelling of “dreamed”) – as well of course as “undreamt.
The dot over the letter “i” and the letter “j” is called a “superscript dot”.