The typical arguments for a dynamic typed language are that it takes less time to write something in it.

The benefits of static typed languages are that your development environment can be a lot smarter (ironically enough leading to faster development speed) and several classes of bugs being unable to happen. In a statically typed language, the IDE can detect if you're trying to call a function that takes a number but you're actually providing a string. In this case the IDE will let you know and you can immediately fix silly mistakes like that.