Sort alphabetically - ignore case
Aa
AA
aa
aa
aA
bb
bb
BB
CC
dD
dD
dD
Sort alphabetically - capitalisation matters
AA
Aa
aA
aa
aa
BB
bb
bb
CC
dD
dD
dD
Sort by frequency - ignore alphabetical order
3: dD
2: aa
2: bb
1: Aa
1: BB
1: aA
1: CC
1: AA
Sort by frequency - then by alphabetical order
3: dD
2: aa
2: bb
1: AA
1: Aa
1: BB
1: CC
1: aA