Ale jak ja mam właśnie się dowiedzieć kiedy będzie policzalne albo niepoliczalne np. słowo currency
You are asking a fundamental question.
To start, first ask yourself (or your English teacher) what dog, non-answer, and chair
mean or name in…
...a lovely species of dog
...a sort of non-answer
...a new kind of chair
I suspect you think that dog
are countable and as such require their "a's". Why then are they used here without any articles?
Do not let your teacher get away with a non-answer like "in phrases such as a sort/kind/species/genre… of X
we do not put "a" before the singular noun X.
If she tries that, ask again: OK, ma'am, but why?
If you do not get a convincing response, try this forum again.