How do ornaments such as trills and grace notes embellish a melody?

In musical composition, ornamentation serves to embellish a melody by adding notes or modifying rhythms to make the music more pleasing or expressive. Ornaments such as trills and grace notes function as small melodic devices that heighten the expressive power of a composition.123

These embellishments function in several ways:
* Variety and Articulation: Ornaments can add variety to repeated musical phrases and assist in the articulation and accentuation of notes.1
* Emotional Expression: Historically, ornamentation has been used to heighten the emotional content of a piece, reflecting the mood of the text in vocal music or serving as abstract expression in instrumental works.1
* Technical Flourish: They allow performers to add complexity and demonstrate skill, though they are often used to enhance the overall character of the melodic line.12

While ornamentation was once largely left to the performer's discretion through improvisation, many ornaments became integrated into the standard musical language by the 19th century, appearing as essential components of the written score.1