The most commonly used letter in the English language is the letter "E." This letter appears disproportionately more often than others in written texts. It plays a significant role in phonetics and is fundamental to word formation, showing up in many common words and phrases. In various analyses of letter frequency, "E" consistently ranks at the top, making it a focal point in puzzles and games such as Scrabble and crossword puzzles. Its prevalence is also evident in literature and digital communication, solidifying its status as the most frequently used letter in English.