One additional remark: Someone mentioned Ada as a language similar to Oberon. I think Nimrod is a much better modern and powerful alternative (with similar syntax) -- the guy(s) seems to be really smart and work very hard on the language. The compiler has some 10k lines of code and compiles itself in a few seconds. And it seems to support nearly all concepts of modern languages like generics, macros, type inference, garbage collection, parallel processing...And performance is already close to C.
But Nimrod is certainly less mature than Ada. It's specification is still unfinished and subject to change. Ada is no such moving target and commercially supported on numerous platforms. You probably should not use some pre-1.0 language implementation to write software that must not fail. And you might find certain features in one language that are not present in the other and vice versa. Then you can't generally say that one is "better". And Ada is not exactly bad. Someone recently wrote a nice article that gives a good impression of its features: http://cowlark.com/2014-04-27-ada/index.html Nimrod is an interesting project though, and its author is certainly not totally unfamiliar with Wirth's work, considering that the Nimrod compiler was bootstrapped with Free Pascal. Both Ada and Nimrod are significantly larger languages than Oberon though and each language ultimately follows a different philosophy. It is up to the user to carefully decide, which one best suits his needs.