Familiarity or solidarity: the pronoun "hi" in basque

The author analyzes the use of the pronouns "zu" (educated form) and "hi" (familiar form), that tend to be compared with educated and familiar forms of "you". However, the author considers that the form "zu" is the normal form that one tends to use, while "hi" is the form that is used between people that live in the same way, and it is therefore not used between friends