External consonant sandhi 3.3.

Question 1

Permitted final letters

Answer 1

all vowels;
consonants: k, ṭ, t, p, ṅ, ṇ, n, m, r, s

Question 2

Basic principle

Answer 2

The basic principle is the resolution of phonetic differencies between juxtaposed consonants. By far most common endings are: t, n and m

Question 3

General rule for final t

Answer 3

when juxtaposed with an unvoiced consonant, t will remain unvoiced. When juxtaposed with a voiced consonant, t will become voiced