A loosely typed language such as PHP is a language that does not require you to declare a variable type when declaring a variable. What does that mean? In PHP when you declare a variable, you can with no need to worry about what kind of data will be stored in that variable.

He compares it to some of the other strictly-typed languages where the variable must be set up and cast to the type and the flexibility that having looser types can have over it. He also looks at some of the drawbacks (ex. can lead to bad code) and advantages (ex. highly dynamic, flexible applications) of this method.