Masc/Fem, Nom-Instr Exceptions

Some 'prestigious' job titles keep their masculine grammar when women have them.
Pscycholog/Pscychologiem
Does this rule apply to Architekt/Architektiem also?

With masculine nominatives that end with 'a' (ASRONAUTA, DENTYSTA) what are the instrumental versions?

LISTONOSZ (Postman)- nominative
e.g. Stefan pracuje jako listonosz
Is the instrumental LISTONOSZIEM?
Stefan jest listonosziem

How do I know when to use -IEM or use -EM?

psycholożka (rare but legit)


architektka

Some 'prestigious' job titles keep their masculine grammar when women have them.
Pscycholog/Pscychologiem
Does this rule apply to Architekt/Architektiem also?


psychologia - psycholgiem
architektura - architektem

astronauta - astronautą
dentysta - dentystą
(this rule appeals to most nominatives ending with -a)

I don't know how are the rules, but z_darius's rule with -IEM/-EM doesn't work with all jobs. Unfortunately I can't guess what the real rule is.

examples:
fizyk - fizykiem
strażak - strażakiem
I suspect that the consonant that closes the word is important here.

agreed
Don;t remember the rules so I'd have to recreate them from memory - a reverse engineering of sorts.

I know that k, g will call for -iem. There is also the issue of consonants softened by final -i.

I betcha Krzysztof will have something up his sleeve.