"Glad" is a feeling with similar denotation as "happy." "Bisy" must be read as "this one" instead of just "this" to form a more proper sentence.
This one, very likely this person, is happy. That one might very well not be.
"This is glad" is not proper English (unless 'Glad' is someone's name, which it isn't in this case). I can't really tell you the rules, since I forgot those a long time ago, men du finner dem vel om du googler det.
Glad is a perfectly good English word, though not very commonly used now. One now most often hears it in the form "I am glad to do X," e.g. "I am glad to meet you." "This is happy" does sound odd to me, but "This one is happy" and "This person is happy" sound perfectly right. I have no idea why.
'This one' is also how many Essosi slaves are taught to refer to themselves, rather than saying 'I'. Missandei corrects herself saying 'this one' instead of 'I' regularly after Dany frees her.
And, in fact, in the very first episode where we hear Valyrian (Astapori Low Valyrian, to be specific), the Unsullied that Kraznys maims says Bezy las kreni, which is the AV equivalent to High Valyrian Bisy kirine issa!
Hmm, as to that I couldn't say. Kraznys does refer to Daenerys as bezy, but that doesn't really answer the question (especially given his attitude towards her.)
Which, of course, is not in question. My only question would be whether Bisy or its descendants is only used by slaves (one wonders about the absence of that category in Westeros) or by freemen as well. Is it truly the opposite of an honorific (I can't remember the proper term for that) or is it simply an archaic usage that is requisite for slaves?
He refers to her as bezy? That's really interesting, because I would have thought he would have used the Astapori descendant of kesy to talk about someone else, essentially to replace the second or third person pronoun. Using bezy for both first and second or third persons sounds incredibly confusing to me. Of course, the Japanese usually get away with not indicating person in any way, so I guess it's possible.
"glad" wasn't issue with the English sentence.
Both "This is happy" and "This is glad" are usually incorrect English. They would refer to very specific things, like showing a happy face and saying "This is happy".
The problem is that happy/glad are adjectives which define people (something alive) and the word "This" by itself doesn't refer to people or a person. It needs help like "This person/one/woman/man/girl/boy/teacher is happy."
I said "This one is happy", because I thought that that could be used to describe someone
It's more like 'I am happy'. Essosi slaves are taught to refer to themselves as 'this one' rather than 'I'. 'This one is happy' is something a slave would say, where as 'I am happy' is something a free man/woman would say.
So would "Kisy kirine issa." be "That one/person is happy"? Hope that makes sense
"Bony kirine issa." = "That one is happy."
The demonstratives that start with "K" refer to inanimate objects.
Bony = That one/animate
Kony = That one/inanimate
Bisy = This one/animate
Kesy = This one/inanimate
OhMyGoT! KIRIMVOSE Stephie, those pronouns were a real deal to master for me. I've been trying to capture their rules and had a good idea, but it's always confusing with some exercises. Now that you listed them in all their meaning and mnemotechnic I'll learn them properly. Kirimvose arlii /-)
But clearly, "bisy" is a common Valyrian term for the first person singular pronoun, so clearly a freeman speaking High Valyrian might use "bisy," which is simply "this one." Perhaps the slaves are simply taught to use the formal High Valyrian form.
Missandei is told by Dany to stop referring to herself as 'this one' after she is freed, so I doubt it's something that's commonly done in Valyrian.
We must keep in mind that there is no "commonly done," of course, in a fictional language, but rather only what Mr Martin or Mr Peterson have imagined, and they may not even have imagined the same thing. Then again, we could distinguish what they had in their heads from what they actually wrote. Thinking about a fictional language is so interestingly different from thinking about a natural one, or even one constructed for use in the real world.