Expression & tempo
Ritardando and accelerando
Ritardando is a gradual slowing of tempo and accelerando a gradual speeding up, both written as abbreviations with a dotted line showing how far they extend.
Ritardando and rallentando are used almost interchangeably, though rallentando traditionally implies a broader, heavier slowing. Both are cancelled by a tempo, which restores the previous speed. Ritenuto, confusingly similar in abbreviation, means an immediate drop in tempo rather than a gradual one.
The common performance failure is slowing too early and having nowhere left to go. Like a crescendo, a ritardando needs its shape distributed across its full written length, with the largest change saved for the final beat or two.
Related terms
Every term in this glossary is taught in context somewhere in Arco's curricula, on the staff, on the keyboard, and on your own fingerboard at the same time.