deriv LSK ETT STT aSTA ALPH OLDHOMEPAGE NEWHOMEPAGE
Most nounbases ending in long vowels are not nounbases proper, but masculine nounbases with a feminine affix added after them (I just call then nounbases for convenience). The lion share of them are a अ bases with /Ap added, and bases with /GI added.
These are a अ bases with /Ap added — **sItA- सीताॱ **azvA- अश्वाॱ **zvetA- श्वेताॱ
These bases are a अ bases with /GI added — **nadI- नदीॱ **vyAghrI- व्याघ्रीॱ **kukkuTI- कुक्कुटीॱ **rAkSasI- राक्षसीॱ
Over 99% of the feminine words that end in the vowel I ई and have at least one other vowel have /GI. As for instance, grammarians consider **nadI- नदीॱ "river" to have been formed from a masculine base nada- नदॱ with the same meaning (that you won't hear anywhere used in practice).
The rare exception to that is the base /lakSmI- f , which is considered by some to be an intrinsic feminine and have no /GI —
/lakSmI- f + /su → !**lakSmIs लक्ष्मीस्
but, for others, it works exactly like a /GI word —
/lakSmI- f + /su → !**lakSmI लक्ष्मी, losing /su by halGyAbbhyodIrgh...
Monosyllables in I ई have no /GI —
**zrI- श्रीॱ "shine, glow"
Both the monosyllables ending in I ई and the monosyllables ending in U ऊ are affected by aciznudhAt....
**bhrU- भ्रूॱ f "eyebrow"
Polysyllables ending in U ऊ,like —
**vadhU- वधूॱ f "wife"
are unaffected by halGyAbbhyodIrgh..., so **vadhUs वधूस् from ← **vadhU- वधूॱ + /su sounds like **vadhUs' वधूस्ऽ from ← **vadhU- वधूॱ + /zas.
Examples of rootnouns —
/grAmaNI- mf "village-leader, maior"
Now time for Q&A.
Which one should I use, **lakSmIs लक्ष्मीस् or **lakSmI लक्ष्मी?
As the saying goes, yathecchasi tathAkuru यथेच्छसि तथाकुरु. Use whatever makes your verses come out right, even in the same verse if you like —
lakSmIr Agacchati kSipraG kSipraM lakSmy apagacchati ||
लक्ष्मीरागच्छति क्षिप्रं क्षिप्रं लक्ष्म्यपगच्छति ॥