Tempos such as vivace (Italian), allegro(Italian), or schnell (German) can usually define a "quick tempo."
Rallentando means slowing the tempo
I would suppose 'ostinato' or, repeat
Adagio is a tempo in music that is very slow.
If you are talking about tempo, it would be [Quarter Note] = [BPM].
The Italian musical term morendo indicates a decrease in volume or tempo, but often affects both; to make the sound slowly die away.
Usually allegro or allegretto can describe a "very fast" tempo.
Allegretto
cheerful or brisk; but commonly interpreted as lively, fast
Tempo.
Allegretto grazioso means fairly fast and gracefully.
"Or else" in English means ossia in Italian musical terminology.
Labradford
To return to the original tempo, "a tempo" is written in the music
The musical term that means to slow tempo is ritardando. If you'd like to slow the tempo very quickly you'd call it a molto ritardando.
yes
Accelerando
keeping the steady beat