I've tried out many different programming languages in an effort to be able to "read" any language that comes my way (as a security researcher, I've noticed malware authors tend not to write in enterprise Java). The only language I can think of off the top of my head where the manual is the only thing you really need is Lua. I don't know if it's just because it's so tiny or because it's a well-written manual (or both), but it's lucky that this is the case because finding Lua code examples isn't exactly easy.

Many other languages I've come across have oddities that pretty much require asking someone who already knows the answer.