Eh, I think that's a little overbroad. The way it works is, methods whose purpose is returning something are named for what they return, while methods whose purpose is creating a side effect are named for what they do. So NSString has `stringByAppendingString:` because you're asking for a new string, while NSMutableString has `appendString:`, which is essentially the same as it would be in Ruby except with an allowance for Objective-C's static type system.

What really creates the impression that Objective-C speaks in terms of nouns is that Cocoa tends to promote immutable objects more than Ruby does (e.g. the only way to get an immutable string or array in Ruby is to freeze a mutable one, while you'll almost never get a mutable array in Cocoa unless you create one yourself), so you probably do spend more time asking your objects for other objects than you do in Ruby.

Although the verbosity can get overwhelming, I actually like this about Objective-C. In terser dynamic languages, I'm constantly having to confirm (either mentally or in the docs) which methods mutate and which return a new object. Cocoa's naming conventions mean I pretty much never have to do that.