i believe "nani wo iu tennan?" means "what are you trying to say?" or something along those lines, so that should work
Nani o shite imasuka? is how you say "What are you doing?" in Japanese if that's what you are asking.
Anata wa kono heya de nani o shite iru no?
「ここで何をしているの(kokode naniwo shiteiruno)?」
何やってんの?
Nani yatte n no?
room in Japanese is "heya".
watashi no heya e youkoso
we say Nakagawa if we want to say inside in Japanese.
To say tennis in Japanese.........テニス
メロン is how you say melon in Japanese.
room in Japanese is "heya".
Ogenki Desuka?
The phrase 'circle room', as in 'circular room' or 'round room', would be translated as 丸い部屋 (marui heya) in Japanese.
watashi no heya e youkoso
''Heya ni WA gomibako ga arimasen'.
a japanese crrency room
"Dou desu ka?" would literally be "how are you doing?" or "how is it?"It is pronounced: doh dess kah.
You could say, "Nani wo shiteru no?" It is also possible to say: "Nani shiteru nan desu ka?"
"I want to make a room reservation" = "Watashi wa heya no yoyaku o shitai".
The translation would be: 何しているの?
Room in Japanese is Heya (pronounced Hey ya)
In Japan Japanese room is called "washitsu". Check it out on Wikipedia.