How Does a Harpsichord Shape Phrases Without Touch Dynamics?

On a harpsichord, each key raises a wooden jack and a quill or similar plectrum plucks the string. The Metropolitan Museum of Art notes that finger force does not directly alter loudness as it does on a piano. Calling the instrument “inexpressive” therefore mistakes expression for crescendo and diminuendo alone.

The player still controls when a note begins, how long it lasts, whether it joins the next note, and whether one voice sounds more connected than another. A slightly shorter bass note can leave air around the melody; a clear separation before a harmonic turn can make the new position audible. The rhetoric comes chiefly from duration, articulation, accent placement and the relationship between voices, not from pressing one key harder.

Some instruments also use stops or two manuals to change which choirs of strings are plucked. The Kunsthistorisches Museum’s 1745 Dulcken harpsichord has two manuals and four registers, allowing quick contrasts of volume and colour. This is not a piano-like continuous crescendo, but a change of level and timbre.

That limitation is useful to pianists. If a phrase can move forward only by becoming louder, its durations, harmonic direction and voicing may not yet be clear. Shape connection and separation first with restrained dynamics; when dynamic variation is added, the music is more likely to speak rather than merely grow louder.

https://www.metmuseum.org/essays/renaissance-keyboards
https://www.khm.at/en/artworks/harpsichord-85228-1
https://www.galleriaaccademiafirenze.it/en/artworks/clavicembalo-espressivo-thomas-culliford-strumenti-musica/