nullaris in Lettic?

I have vague rumours (English Wikipedia) that Lettic has a
numerus nullaris, designing that there is nothing of something. Is
this true and is there someone on this list that can make this clear?

I imagine that this non-numerus is shown by special endings, like
plural and dual.
I further imagine that, considering Fennic adstratum and substratum,
this might be a form of ablative (cf "n'et borshcha") having lost its
negation (or having it 'sous-entendue¨').

How about this speculation?

Lars