They are often used together poetically, but keep in mind that English has its origins in both the romance languages (with the arrival of the Normans) and germanic languages (e.g. Anglo-Saxons). As such, "Freedom" is of Germanic origin, whilst "Liberty" is of French origin. This happens a lot - we often have word pairs from both languages :) French: Liberté Latin: Libertas German: Freiheit Low German: frīdom Modern Dutch: Vrijheid Middle Dutch: vrijdom