Natural selection in verbs

To understand why we lost certain verbs or words, a guide into Zipf's law, proposed by linguist Geo­rge K Zipf, would be necessary

Recently at a friend’s place, I encountered Beowulf, an Old English epic poem written probably between the 8th century and the 11th century. Understanding it was tough, even with translations — and tougher for someone like me who would rather read a graphic novel (and I do not mean children comics) than diving into classic or modern literature. 

I failed miserably, but the arduous 20-minute journey into Beowulf sparked a curiosity: Why words either evolve or get lost? Why words like “swelce (also)” and “findan (to find)” don’t exist anymore? Well, that rese­arch is still on (much simpler: I am bored