Sociolinguistics 9, Exercise 1: three generations

As shift: the community has become bilingual (parents use A and B) and is
moving its allegiance to the second language; the children use only B at home.
The Language shift article measures shift "across generations" as the share
using the second language at home, so this village shows it clearly.

Which generation matters most: the children's. The Endangered language article
says UNESCO centres on intergenerational transmission: a language is endangered
when speakers stop passing it on, with no new speakers, adults or children.
Here A is no longer being passed on at home.

A cause from the page that could explain it (any one): economic (migration
to cities), political (education only in the majority language), cultural
(speakers see their language as backward), or prestige and mobility. Which one
fits this village is not stated, so the choice is a guess.

Source: Wikipedia, Language shift; Endangered language.