Compose a piece of music that follows both the given musical theme and the letter-based structure provided.
X:1
L:1/8
Q:1/4=120
M:6/8
K:Emin
['dBB AGA GAG GAB dBB BAB', 'g2 g faf ded def']  
X:1
L:1/8
Q:1/4=120
M:6/8
K:Emin
"^Irish Jig." ue | dBB AGA | GAG GAB | dBB BAB | Bee efg | dBB AGA | GAG GAB | dBB BAB | Bee e2 :| 
 uf | g2 g faf | ded def | vg2 vg faf | efe e2 f | g2 g faf | ded def | gfe dBA | Bee e2 |]  