It would be rather jedanaest, dvanaest, trinaest (at least in Croatian) - your version sounds how it is shortened in pronounciation in some regions.
Also šezdeset with "z".
Hi, yes, I assumed it would be the case. And it is not always easy to explain word terminations/cases. Especialy if you do not use it regularly or is limited to family interactions. I would guess your pronouncian might come from either some parts of Lika/Dalmatia or Bosnian part closer to Croatia. Is it the case?
