The letter "ъ" is a unique character in the Cyrillic alphabet, primarily used in the Russian language. It is known as the "hard sign" and serves to indicate a slight pause between consonants and vowels, affecting pronunciation. It does not have a sound of its own but modifies the sounds of surrounding letters. In addition to Russian, "ъ" appears in other Slavic languages that use the Cyrillic script, such as Bulgarian. In Bulgarian, it can also function as a marker for the end of a word. Its usage has diminished over time, but it remains an important part of the alphabet in these languages.