Comparing type systems of common languages

From http://en.wikipedia.org/wiki/Comparison_of_programming_languages:

Language	Type strength	Type safety	Expression of types	Compatibility among composite types	Type checking
C#	strong	safe	explicit	name-based	static
Clojure	strong	safe	implicit with optional explicit typing		dynamic
Erlang	strong	safe	implicit		dynamic
F#	strong	safe	implicit	name-based	static
Fortran	strong	safe	explicit	name-based	static
Go[26]	strong	safe	implicit with optional explicit typing	property-based	static
Groovy	strong	safe	implicit with optional explicit typing		dynamic
Haskell	strong	safe	implicit with optional explicit typing	property-based	static
Java	strong	safe	explicit	name-based	static
JavaScript	weak		implicit		dynamic
Objective-C	weak	safe	explicit	name-based (subclassing) and property-based (protocols)	dynamic with optional static typing
OCaml	strong	safe	implicit with optional explicit typing	property-based	static
Perl 6			partially implicit		dynamic with optional static typing
PHP	weak		implicit		dynamic
Python	strong	safe	implicit	property-based	dynamic
Ruby	strong	safe	implicit	property-based	dynamic
Scala	strong	safe	partially implicit (local type inference)	name-based (subclassing) and property-based (structural)	static
Scheme	strong		implicit		dynamic (latent)
Smalltalk	strong	safe	implicit		dynamic
Standard ML	strong	safe	implicit with optional explicit typing	property-based	static
Visual Basic .NET	strong	unsafe	explicit		static