1. The most common letter in English is "e".
    
2. The most common vowel in English is "e", followed by "a".
    
3. The most common consonant in English is "r", followed by "t".
    
4. Every syllable in English must have a vowel (sound). Not all syllables have consonants. 
    
5. Only two English words in current use end in "-gry". They are "angry" and "hungry".
    
6. The word "bookkeeper" (along with its associate "bookkeeping") is the only unhyphenated English word with three consecutive double letters. Other such words, like "sweet-toothed", require a hyphen to be readily readable.
    
7. The word "triskaidekaphobia" means "extreme fear of the number 13". This superstition is related to "paraskevidekatriaphobia", which means "fear of Friday the 13th".
    
8. More English words begin with the letter "s" than with any other letter.
    
9. A preposition is always followed by a noun (ie noun, proper noun, pronoun, noun group, gerund).
    
10. The word "uncopyrightable" is the longest English word in normal use that contains no letter more than once.
     
11. A sentence that contains all 26 letters of the alphabet is called a "pangram".
     
12. 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.
     
13. 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" :)
     
14. A word formed by joining together parts of existing words is called a "blend" (or, less commonly, a "portmanteau word"). Many new words enter the English language in this way. Examples are "brunch" (breakfast + lunch); "motel" (motorcar + hotel); and "guesstimate" (guess + estimate). Note that blends are not the same as compounds or compound nouns, which form when two whole words join together, for example: website, blackboard, darkroom.
     
15. The word "alphabet" comes from the first two letters of the Greek alphabet: alpha, bēta.
     
16. The dot over the letter "i" and the letter "j" is called a "superscript dot".
     
17. In normal usage, the # symbol has several names, for example: hash, pound sign, number sign.
     
18. In English, the @ symbol is usually called "the at sign" or "the at symbol".
     
19. If we place a comma before the word "and" at the end of a list, this is known as an "Oxford comma" or a "serial comma". For example: "I drink coffee, tea, and wine."
     
20. Some words exist only in plural form, for example: glasses (spectacles), binoculars, scissors, shears, tongs, gallows, trousers, jeans, pants, pyjamas (but note that clothing words often become singular when we use them as modifiers, as in "trouser pocket").

Source: Englishclub.com