Just as the most typical masculine nouns are those that end in o, the most typical feminine nouns are those ending in i. But in the case of these nouns, the manner in which they change from their singular to their plurals depends on one peculiar property of theirs: whether they have a single or a double consonant before that i. By single or double consonant I am not referring to the number of consonant letters but the number of consonant sounds. For example, the dd in koddi
1. Feminine nouns which end in i, and have a single consonant before the i, form their (nominative) plurals by changing the i to iô.
Examples: boddi
2. Feminine nouns ending in i, and having a double consonant before that i, form their plurals by changing the i into eô.
Examples: sotri
Note: An m or n that nasalizes the preceding vowel (and hence takes the place of an anuswara), is not considered as a vowel. Thus panthi
3. Some feminine nouns, ending in a consonant, form their plurals by taking on an extra vowel ô.
Examples: sangh
4. Other feminine vowels, ending in a consonant, form their plurals by adding an i instead.
Examples: kidd
Note: There is unfortunately no rule to tell us which feminine nouns should take an i and which should take an ô to form their plurals. Also, in some of these cases, the noun may drop its last vowel before taking the new ending to form the plural and there is no general rule that covers that either. For example: the plural of rampônn is rampnni. That has to be learnt as a part of the vocabulary. For instance, it might interest you to know that the word chinch
5. Feminine nouns ending in a remain unchanged in the plural. Examples: pidda