Nakala asilia - Kilatini - istud ipsu

"istud" originou a palavra "isto"
e
"ipsu" originou a palavra "isso"
em português e gostaria de saber a diferença entre estas duas.
..............................................................
"istud" is the root of the word "isto"
e
"ipsu" is the root of the word "isso"
in portuguese and I would like to understand better the diference beetwen this two words.