The introduction to me reads as very confused:

One of the most sought-after features for PHP is Generics: The ability to have a type that takes another type as a parameter. It's a feature found in most compiled languages by now, but implementing generics in an interpreted language like PHP, where all the type checking would have to be done at runtime, has always proven Really Really Hard(tm), Really Really Slow(tm), or both.

* The topic of the article is implementing generics at compile time, but this claims that PHP is not compiled.

* Type checking is orthogonal to compilation vs interpreter.

* Types are not checked at runtime. It is kinda the point of types that they are checked before code runs. Runtime checks are on values. You can reify types at runtime but this breaks a useful property of generics (parametricity) and it prevents the very useful feature of types without a runtime representation (often known as newtypes).

* If you want to use types in the colloquial "dynamic type" meaning as tags on values, and you also want to talk about generics (a feature that only makes sense for types-as-compile-time-properties) you need to be really careful in your terminology or confusion will abound!