Uncopyrightable, with 15 letters and not a single one repeated. Dermatoglyphics, the study of fingerprints, works too.

Abracadabra

Fish. The gh is pronounced as in tough, the o as in women and the ti as in nation. Ghoti is a constructed word to illustrate irregularities in English spelling.

A = 1
B = 3
C = 9
D = 17

1 lb = A
2 lbs + A = B
3 lbs = B
4 lbs = A + B
5 lbs + A + B = C
6 lbs + B = C
7 lbs + B = A + C
8 lbs + A = C
9 lbs = C
10 lbs = A + C
11 lbs + A = B + C
12 lbs = B + C
13 lbs = A + B + C
14 lbs + B = D
15 lbs + B = A + D
16 lbs + A = D
17 lbs = D
18 lbs = A + D
19 lbs + A = B + D
20 lbs = B + D
21 lbs = A + B + D
22 lbs + A + B = C + D
23 lbs + B = C + D
24 lbs + B = A + C + D
25 lbs + A = C + D
26 lbs = C + D
27 lbs = A + C + D
28 lbs + A = B + C + D
29 lbs = B + C + D
30 lbs = A + B + C + D

It’s a palindrome (a word or phrase that’s spelled the same backwards and forwards).