This is a follow up to the original counting days entry. We're going to discuss the words for relative days.
The word for day is Nopu, which is where all of these words are derived. To say today we can simply add the demonstrative suffix -ru. This translates literally as "this day", which is the equivalent to today in English.
Similarly yesterday is Nopu+la, or "past day". Tomorrow is Nopu+fu, or "future day".
Nopuru - Today
Nopula - Yesterday
Nopufu - Tomorrow
We can use similar constructions to say expressions like "day before yesterday". In Reisu this would be Nopulatu, "day-past-two".
We can use these same constructions for other time words like month or year. The nopu in brackets are not required if it's obvious by the context that we aren't talking about the literal sun and moon.
[Nopu]rigila - Last year
[Nopu]lakifu - Next month
Koxukusifutu - Two weeks from now