right, most languages do this now. But F# extends that further. Function signatures don't need types either. Record types can be inferred from their field names

right, most languages do this now. But F# extends that further. Function signatures don't need types either. Record types can be inferred from their field names. If you write a function with no type signatures it is automatically made generic, as well. So you can often write large chunks of code with no specified types, but everything is still statically typed. Granted this is maybe not always good, sometimes it is productive to have types in the function signatures, though the IDE can supply these automatically with codelens featuers/on hover features.