#1
Learning fire and rain from James Taylor. There is a section strumming the same chord but each strum sounds different. Above each note there is a symbol MP MF F and P. What do these mean? I am sure it is why each strum sounds different
#2
M = moderate
MF = play slightly louder than moderate
MP = play slightly softer than moderate
P = play softly
F = play loudly
FF = play very loudly

Also, Fire and Rain includes A, Asuss2, and A7 (basic lift/hammer variations).
#3
Dynamics - volume....

Calando quietening Becoming softer and slower
Crescendo growing Becoming louder
Decrescendo shrinking Becoming softer
Diminuendo dwindling Becoming softer
Forte strong Loud
Fortissimo very strong Very loud
Mezzo forte half-strong Moderately loud
Piano gentle Soft
Pianissimo very gentle Very soft
Mezzo piano half-gentle Moderately soft
Sforzando strained Sharply accented

Notice the "P", (piano or soft), And the "M" and the "F" also.

Pretty much all musical terms are in Italian, the same way that ballet terms are in French.....Here's the full Wiki page: http://en.wikipedia.org/wiki/Italian_musical_terms_used_in_English