"Mais il n'y a pas de mousse" means "but there is no moss / foam / mousse" in English.
"n'est pas" means "is not" in English.
I love you, but I can not tell you.
mais tu n'es pas prêt / pas prête
It means "not that".
" ... n'est pas heureuse " means "... isn't happy" in English. "ne pas heureuse" means "not happy", but is a fragment.
"mais je n'ai pas de soeurs"="but I don't have any sisters".
I only have sisters, but no brothers.
You made a mistake, in French you have to say : "mais je ne te reconnais pas" = "But, I don't recognize you"
"Mais ce n'est pas le joyeux ..." means "but is is not the merry ..."
Je suis désolé mais je ne parle pas anglais means "I'm sorry but I don't speak English."
"mais jtm pas" is a text message meaning "but I don't like you" full text: "mais je ne t'aime pas"
je ne vous connais PAS mais vous semblez étonnant means 'I don't know you, but you seem amazing' in English.
"But you didn't have any!" is an English equivalent of the French phrase Mais tu n'en avais pas! The pronunciation will be "meh tyoo naw-na-veh pa" in French.
You can say "mais pourquoi pas" in French to ask "but why not".
"Je ne suis pas français mais je parle couramment" means 'I'm not French but I speak fluently"
"pas mort, mais endormi" (feminine: pas morte, mais endormie)
"but I cannot teach it to you because I do not have a good English language level."