I mean the last 4 English month names are basically <#>month, but never got updated when the Romans switched from a 10 month calendar to a twelve month calendar. The suffix -ber comes from the latin word for month, with the prefix being the Latin number Septem = 7, Octo = 8, Novem = 9, Decem = 10. The two new months (January and February) were inserted at the start of the year throwing the naming off by 2.

July and August were originally called Quintilis and Sextilis so the 5th and 6th months and renamed after the calendar change, to honour Julius and Augustus.