English for Today by Ganiu Abisoye Bamgbose (Dr GAB)
Grammar of Reference
He comes here ~one day on, one day off~ (nonstandard).
He comes here *every other day* (standard).
If something happens every other day, every other year, etc., it happens, then does not happen, then happens again, and so on, in a regular pattern.
We go there ~every two two weeks~ (nonstandard).
We go there *fortnightly* (standard).
A fortnightly event or something that happens fortnightly appears once every two weeks.
I saw him ~day before yesterday~ (nonstandard).
I saw him *the day before yesterday* (standard).
Note that the definite article, the, is sacrosanct to the correctness of the phrase.
GAB