накапливаться означает в английский

build up▼(to accumulate)
verb
[UK: bɪld ʌp] [US: ˈbɪld ʌp]

accumulate [accumulated, accumulating, accumulates]▼(to grow in number)
verb
[UK: ə.ˈkjuː.mjə.leɪt] [US: ə.ˈkjuː.mjə.ˌlet]

backlog▼(to acquire something as a backlog, or to become a backlog)
verb
[UK: ˈbæk.lɒɡ] [US: ˈbæk.lɔːɡ]

pile up▼(idiomatic: to accumulate)
verb
[UK: paɪl ʌp] [US: ˈpaɪl ʌp]

stack up▼(accumulate)
verb
[UK: stæk ʌp] [US: ˈstæk ʌp]