Well, for some words that is correct, e.g. muña, taoba, riña etc. but for, "azantys" the plural is, "azantyssy" and for, "hontes" the plural is, "hontesse".
The high valyrian course has just recently started to get audio (like less than a week), so most of the words and phrases still miss audio. But they will get it soon :)
And the i in the end of issi sounds like the i in the beginning of the word :)