How the word for Seven has changed

B ← A   indicates that the word in language B has evolved directly
from a word in language A, or at least a very similar language. For
example, Persian did not evolve directly from Avestan, but the Old
Persian texts lack the more extensive vocabulary of the similar     
Avestan language. Alternatively, the word could be borrowed        
from another language. English is full of words borrowed from      
Old French.

Abbreviations at bottom of page
* = hypothetical, reconstructed