i learned electronics at a young age, and could read schematics by age 11. my grandfather had some german made shortwave radios (i still have his Blaupunkt), and the schematics were in a pouch inside the back of the cabinet. once i understood the rectangles were resistors, and the variations in the other symbols (and that commas were used instead of decimal points), they weren't that hard to read, but i still prefer the american symbols, but find some of the european conventions useful (such as a dashed circle around transistors indicating that they are on a heat sink). somebody mentioned the logic gate symbols? technically, the american (easy to read) symbols were supposed to be phased out as obsolete, but because they are so easy to read, people keep using them. unfortunately, though, there are relatively new symbols for D/A and A/D converters that are somewhat confusing, because they look the same.