I recommend that you need to teach the translator about the markup. It's really easy to understand.

The way L10ns try to mitigate the complexity of the markup language is to provide buttons for pasting the correct markup for translators. Also a developer translates on his own language first. And this example will always be visible to the translator of an another language for easy reference. So the programmer offloads the logic thinking from the translator.

IMO ICU's messageformat markup is also slowly becoming the standard for localizing strings. It is already used widely by big organizations such as Apple, Google and Yahoo.

L10ns pre-compiles all message string. So it offloads the parsing performance.