The letter "ь" is known as the soft sign in the Cyrillic alphabet, used in languages such as Russian and Ukrainian. It does not represent a sound on its own but modifies the preceding consonant, making it softer. This means that the consonant is pronounced with a slight palatalization, which affects the way words are spoken. In written form, "ь" appears at the end of words or before certain vowels. It plays a crucial role in distinguishing meanings between words that would otherwise look similar. For example, in Russian, "мать" (mother) and "мат" (curse) differ in pronunciation due to the presence of the soft sign.