I have two bank accounts, and I use them alternatively each month.
"I have two bank accounts, and I use them alternatively each month."
＊ bank account: 銀行口座
＊ alternatively: 交互に
＊ each month: 毎月
I have two bank accounts and I switch between them each month.
I alternate between my two bank accounts each month.
毎月 - each month
銀行口座 - bank account
銀行口座を持ってる - have a bank account
私は銀行口座を持っている - I have two bank accounts
毎月 - every month, each month
交互 - alternate between, switch between, swap
使う - use
交互に使う - use a different one, switch between and use
毎月それを交互に使っている - switch between them (and use) each month