How we cite our quotes:
Old Man: "Ah! This house, this island, I can't get used to it. Water all around us...water under the windows, stretching as far as the horizon." (10)
The old couple is completely isolated. As the Old Man says, their house is totally surrounded by water, leaving them pretty much alone with each other. Some critics suggest that the play is set in a post-apocalyptic world. It could be that the Old Man and Woman are the only two people left on earth, and that's about as isolated as it gets.
Old Man: "I'm an orphan, on earth, you're not my mamma..." (87)
The Old Man suddenly feels incredibly isolated as he remembers that his mother is dead. His wife tries to take the place of his mother, but he rejects her. Nothing can replace his mother, so now he'll forever be "an orphan." Of course, you could interpret the whole orphan thing as a metaphor for all of humanity. If human beings are alone in the universe, as the play seems to suggest, then we are all very much like poor little orphans cut off from the support and comfort that our metaphorical "parents" might give us.
The Old Woman: "in our own words, we find perhaps everything ... and then we are orphans no longer." (122)
The Old Woman seems to be saying that language is the key to escaping isolation. It kind of makes sense, right? We use words to articulate our thoughts and emotions. Without them, we would be unable to communicate most of what we think and feel.