There are many expressive words written in different languages that indicate how a piece of music should be played. Sometimes such an expression may be placed immediately after the tempo mark. They are placed anywhere in music so as to express musical ideas at that instant, and can not easily be expressed by symbols.

Italian Terms:

a:                      for, at, in, etc.
a capella:              for choral music without accompaniment.
a capriccio:            in a humorous manner.
accelerando (accel.):   gradually getting faster.
ad libitum:             at the performer's liberty.
affectuoso:             affectionate, with tender warmth.
agitato:                agitated, excited.
alla:                   in the style of.
alla breve:             the half note rather than the quarter note takes the beat.
allargando:             growing broader.
amabile:                sweet, amiable, lovable.
amoroso:                loving.
ancora:                 again.
animato:                with spirit.
a piacere:              at the performer's discretion
appassionato:           impassioned.
arioso:                 a short solo in the style of an air.
arpeggio:               the notes of a chord are played in succession rather than simultaneously.
assai:                  very.
ben, bene:              well.
brillante:              with brilliance or vivacity.
cadenza:                a passage for solo instrument in free, improvisatory style.
calando:                diminishing in dynamic and speed.
cambiare:               to change.
cantabile:              in a singing style.
chiuso:                 stopped, in horn playing.
col, colla:             with the.
come:                   like, as.
comodo:                 comfortable, easy.
con:                    with.
con brio:               with brilliance or vivacity.
con dolore:             with sorrow.
con forza:              with force or strength.
con fuoco:              with fire.
con giusto:             with taste, fitting mood and tempo.
con passione:           with passion.
con spirito:            with spirit.
coro:                   chorus.
crescendo:              gradually get louder.
dal:                    from the.
decrescendo:            gradually get softer.
deciso:                 with decision.
delicato:               delicately.
diminuendo:             gradually get softer.
dolce:                  sweetly.
dolente:                doleful, sorrowful.
doppio movimento:       double the preceeding speed.
e, ed:                  and.
e poi:                  and then.
espressivo:             expressive.
facilimente:            easily, without strain.
feroce:                 ferocious.
fine:                   end, close.
furioso:                furiously.
giocoso:                gay, playful.
grandioso:              grandly.
grazioso:               graceful.
il, la:                 the.
impetuoso:              in an energetic manner.
lacrimoso:              tearfully.
lamentoso:              in a mournful style.
largamente:             in a dignified manner.
legato:                 smoothly.
leggioro:               light and graceful.
lusingando:             alluring, flattering.
ma:                     but.
maestoso:               majestically.
mancando:               dying away.
marcato:                emphasized.
martellato:             hammered stroke played with very short bows at the point.
marziale:               march-like.
meno:                   less.
meno mosso:             less movement, slower.
mesto:                  mournful, sad.
mezzo:                  half.
misterioso:             mysteriously.
molto:                  much, very.
morendo:                dying away and becoming slower.
nobilimente:            nobly.
non:                    not.
ossia:                  or.
parlando:               singing in speaking style.
parlante:               singing in speaking style.
pateticamente:          pathetically.
perdendosi:             dying away and becoming slower.
pesante:                heavy, weighting.
piacevole:              agreeable.
piangevole:             plaintively.
piu:                    more.
pizzicato:              pluck the string with the finger.
placidamente:           peacefully.
pochetto:               very little.
poco:                   little, a little.
poco a poco:            little by little.
poi:                    then.
pomposo:                pompous.
quasi:                  almost.
rallentando (rall.):    gradually getting slower.
religioso:              with devotion.
replica:                repeat.
risoluto:               resolutely.
ritardando (rit.):      gradually getting slower.
ritenuto (riten.):      suddenly slower, held back.
ritmico:                rhythmical.
rubato:                 robbed time, speeding up and slowing down.
scherzando:             playfully.
secco:                  dry, short.
sempre:                 always.
semplice:               simple.
senza:                  without.
serioso:                serious.
simili:                 the same.
sino al:                up to the...
slargando:              broadening.
slentando:              getting slower.
smorzando:              smother dynamic to nothing.
soave:                  suave, gentle.
solennemente:           solemnly.
sombre:                 dark, somber.
sonore:                 sound with full tone.
sordino:                mute.
sostenuto:              sustained.
sotto voce:             with a barely audible sound.
spiccato:               with a light bouncing motion of the bow.
spiritosso:             lively, with spirit.
staccato:               detached, short.
stentando:              delaying, retarding.
strepitoso:             noisy.
stringendo:             quickening.
subito:                 suddenly.
sul:                    on the...
suono:                  sound, tone.
tanto:                  so much.
tempo primo:            return to original time.
tempo rubato:           robbed time.
teneramente:            tenderly.
tenuto:                 held, sustained.
tessitura:              average range of a vocal part.
tosto:                  rather.
tranquillo:             tranquil, quiet, calm.
tremolo:                a quick reiteration of the same tone on a string instrument.
tristement:             sadly.
troppo:                 too much.
tutti:                  all.
un poco:                a little.
vibrato:                slight change of pitch on same note.
vigoroso:               vigorous, strong.
vivo:                   lively.

German Terms:

aber:                   but.
ausdruckswoll:          with expression.
beruhigen:              to calm, to quiet.
bewegt:                 agitated.
bewegter:               more agitated.
daher:                  from there.
dämpfer:                mute.
drängen:                pressing on.
einleiten:              to lead into.
erschütterung:          a violent shaking, deep emotion.
etwas:                  somewhat, rather.
flüchtig:               fleeting, transient.
frei:                   free.
ganz:                   entirely, altogether.
gebrochen:              broken.
gedehnt:                held back.
gemächlich:             comfortable.
geschlagen:             struck.
gesprochen:             spoken.
gesteigert:             intensified.
gestopft:               stopped note by placing the hand in the bell of the horn.
gewöhnlich:             usual, customary.
gleichmässig:           equal, symmetrical.
hauptstimme:            most important voice in the phrase.
halbe:                  half.
halt:                   stop, hold.
hauptzeitmass:          original tempo.
heftiger:               more passionate, violent.
hervortretend:          prominently.
hörbar:                 audible.
immer:                  always.
klangvoll:              sonorous, full-sounding.
klingen lassen:         allow to sound.
kräftig:                strong, forceful.
kurz:                   short.
lebhaft:                lively.
leidenschaftlich:       passionate.
mit:                    with.
nebenstimme:            the second most important voice in the phrase.
nehmen:                 to take.
neue:                   new.
nicht:                  non, not.
noch:                   still, yet.
ohne:                   without.
plötzlich:              suddenly.
ruhig:                  calm.
schleppend:             dragging.
schon:                  already.
schwerer:               heavier, more difficult.
schwermütig:            dejected, sad.
sehr:                   very.
sprechstimme:           speaking voice.
trauernd:               mournfully.
übertönend:             drowning out.
unterbrechung:          interruption, suspension.
verhalten:              restrained, held back.
verklingen lassen:      let die away.
verzweiflungsvoll:      full of despair.
vorwärts:               forward, onward.
weg:                    away, beyond.
wieder:                 again.
wie oben:               as above, as before.
zart:                   tenderly, delicately.
ziemlich:               suitable, fitting.
zurückhaltend:          slowing in speed.
zurückkehrend zum:      return to...

French Terms:

bien:                   very, well.
come:                   like.
détaché:                detached.
doux:                   soft, light.
echoton:                with an echo.
éclatant:               sparkling, brilliant.
encore:                 again.
en dehors:              outside, emphasized.
en fusée:               dissolving in.
et:                     and.
fois:                   times, as in number of.
laissez vibrer:         let vibrate.
lié:                    tied.
main:                   hand (droite right; gauche left).
marqué:                 marked, with emphasis.
pause:                  pause, rest.
peu:                    little.
plus:                   more.
sans:                   without.
seulement:              only.
sombre:                 somber, dark.
son:                    sound.
sourdine:               mute.
soutenu:                held, sustained.
sur:                    over, on.
très:                   very.
tristement:             sadly.
unison (unis.):         same pitches played by several instruments.