@endings after neuters

The basic endings for cases 1 and 2 are /su /au /jas /am /au /zas. But after neuter bases, they are replaced with /luk, /zI, /zi.

Therefore, after a neuter the first and the second will always look the same. With the possible exception of the /sambuddhi — to address a banana in correct Sanskrit you say he kadalIphala हे कदलीफल, with no m म्.

singular

/su and /am disappear by svamornapuMs... —

manas- मनस् n + /su OR /am
→ manas मनस् + /luk by svamornapuMs... (not by halGyAbbhyodIrgh...)
→ manas मनस् " s o mind"

nAman- नामन् n + /su OR /am
→ nAman नामन्
→ nAma नाम losing n न् by nalopaHprAt....

But after neuter -a- ॱअॱ bases, only the /sambuddhi turns into /luk; after those the normal /su turns into /am, and /am stays —

phala- फलॱ + /su OR /am
→ phala- फलॱ + /am by atom
→ phalam फलम् by amipUrvaH

phala- फलॱ + /sambuddhi
→ phala फल by eGhrasvAtsamb...

dual

/au usually turns into /zI by napuMsakAcca —

**phale फले

manas- मनस् n + /au
→ manas- मनस् + /zI by napuMsakAcca
→ manasI मनसी.

plural

/jas and /zas, after most neuters, turn into /zi (by jazzasozziH). This /zi is strong by zisarvanAm..., so it gives /num to most bases, by napuMsakasy.... Also most lengthen the base vowel by sarvanAmasth... or sAntamahat... or other rules:

phala- फलॱ n + /zas → **phalAni फलानि

madhu- मधुॱ n + /zas → **madhUni मधूनि

manas- मनस् n + /zas → **manAMsi मनांसि

cakSus- चक्षुस् n + /zas → **cakSUMSi चक्षूंषि