I’ve been working in Modula-2 for last few weeks. It’s a considered a dead language now, one of Pascal’s descendants designed by Niclaus Wirth. I’ve been doing some updates to quite an old project, embedded system for military usage. I had to run Mac OS 7.5 emulator to get original 1989 compiler running. Modula-2 dialect understood by this compiler is quite strict – you cannot even mix cardinal and integer numbers without explicitly converting one of them.
First difference you may notice (compared to Pascal) is case sensitiveness of Modula-2, for instance all reserved words are upper cased. You don’t have to write so many begin-end statements though. Another C-like trait is importance of header files (definition modules) order during compiling – just change it a little bit in a large project and whole thing breaks down.
More info about Modula-2 if you’re interested: http://www.modula2.org/.