Expressions for dynamics:

What are dynamics?: Dynamics are changes in volume during a piece of music. Conductors and musicians today might use English words like 'louder' or 'quieter' but formal notation will include various Italian words along with graphic music notation to indicate changes in dynamics e.g. getting louder.

Dynamic markings:

pp: pianissimo - very quiet

p: piano - quiet

mp: mezzo-piano - relatively quiet/soft

mf: mezzo-forte - relatively loud

f: forte - loud

ff: fortissimo - very loud

Changes in dynamics:

crescendo: gradually getting louder (often written as cresc.) It is shown by a horizontal V getting wider as the music progresses.

decrescendo: gradually getting softer (often written as decresc.) It is shown by a horizontal V getting smaller as the music progresses.

diminuendo: same as decrescendo but also slowing down and getting softer. (often written as dim.)

Example:

Here is an extract from Ex. 3: Franz Schubert, Erlkönig D. 328 for a vocalist and piano accompaniment. You can clearly see the markings for crescendos and decrescendos in underneath the vocal line. You can also see the markings for piano and forte underneath the accompanying piano lines. This is used to create emotion and expression.

Here is also a video showing the changes of dynamics from a piece by Anton Bruckner (excerpt from the 4th movement (out of 4) of his Symphony N.4 "Romantic"). You can hear the changes in dynamics in the music clearly. This helps to understand how loud/quiet a musician should be playing dynamic markings.

Why do we use dynamic markings?:

Dynamic markings are used to add expression and emotion to the piece. Instruments sound different when played at different volumes e.g. horns and brass sound better when they are played forte. Dynamics can also be used to help create moods and atmosphere. For example a crescendo can be used to evoke feelings of tension, anticipation and excitement. Dynamic markings are written to help musicians be aware of these changes in advance so that they can recreate the piece to a more accurate standard and produce the intended emotion / mood.