The letter “D” is a consonant in the English alphabet and it is the fourth letter of the alphabet. The sound of the letter “d” is created by pressing the tip of the tongue against the roof of the mouth behind the front teeth and then releasing it with a burst of air. The letter “d” is used in many words in the English language and it is an important component in constructing words and sentences. Additionally, the letter “d” is used in many other languages and writing systems around the world.