no, we are talking about a dynamic programming language, not a dynamically typed programming language.<p>The name of the language 'Dylan', he is using, is short for 'Dynamic Language'.<p>You can read about Dylan in the Foreword, Preface and Introduction of its manual:<p><a href="http://lispm.dyndns.org/documentation/prefix-dylan/book.annotated/annotated-manual.html" rel="nofollow">http://lispm.dyndns.org/documentation/prefix-dylan/book.anno...</a><p>Common Lisp and Dylan were 'sold' as 'OODL', Object-oriented Dynamic Languages. Norvig argues in the context of OODLs like Common Lisp (CLOS), Dylan, and related (say, Smalltalk).<p>'Dynamic' in this context does not mean 'dynamically typed', but being capable of changing the language, its implementation or the program - while the software is running.<p>Dynamic features are:<p>* adding, removing, changing classes<p>* adding, removing, changing methods<p>* reflection<p>* introspection<p>* meta object protocol<p>* first class representations of classes, methods, ...<p>* changing the class inheritance<p>* changing an object from one class to another<p>and more.