Largo: Very Slow
Andante: Walking Tempo (moving along)
Moderato: Medium speed. Can be combined with any other tempo to modify it.
Allegro: Quickly, Cheerfully
Vivace: Lively and very fast.
Ritardando: Gradually getting slower
Accelerando: Gradually getting faster
A Tempo: the marking that tells you return to your original speed after ritardando or accelerando
Tacet: Do not play this part. Listen while others are playing.