Spanish diacritical marks are symbols used to modify the pronunciation of Spanish words. The most common of these is the tilde, which is a diacritic mark that appears over the letter 'n' and is used to indicate a nasal sound. The tilde is also used to indicate a palatal nasal sound in some dialects of Spanish. In addition to the tilde, other Spanish diacritics include the acute accent, the grave accent, and the diaeresis. These marks are used to indicate stress, vowel length, and syllable breaks.