"This doesn't replace the female boomer, and if you want a soundless version open up the vpk and remove the sound files, otherwise load whatever sounds you prefer higher in the mod list, so that they load instead of Patrick's voice."

As the mod author said, all you need to do is open the vpk. "How do I do that, McJeb?" you may be asking. Well, I'll get to that in a minute. Many modding for beginners guides revolve around a special 3rd party download of some kind, what kind of software or tool this is depends on the kind of mod and what game it is for. The 3rd party software that is commonly used in the beginner guides are more flexible, reliable, and user-friendly than the original official tool; however, the software has to be downloaded from a site, and some sites, such as the site you download GCFscape from, are outdated and insecure. Unlike the beginner guides suggest, you do not absolutely require a 3rd party tool, after all, how did anyone make a mod before someone made a 3rd party modding tool, they used the official tools of course!

First you'll need the Left 4 Dead 2 authoring tools. Navigate to your library, then go to "All" and change the filters so that only "Tools" are selected, then scroll through it until you find the Left 4 Dead 2 authoring tools. Install the Left 4 Dead 2 authoring tools, and then navigate into your Steam folder, then navigate to the Left 4 Dead 2 game files inside (leave a comment if you do not know how to do that). Go to the left4dead2 folder and then the addons folder and, if you installed the mod and launched Left 4 Dead 2 afterwards, you should see the vpk file for this mod. You won't be able to tell if it is this mod by the file name, but if you look at the image of the same name as the vpk file then you should know what addon it is.
Inside the bin folder, which is located outside the left4dead2 folder (the bin folder be directly in the Left 4 Dead 2 folder), you will see vpk.exe.
If you didn't install the Left 4 Dead 2 authoring tools, then you won't see vpk.exe.
vpk.exe is the vpk tool and if you drag a vpk onto it then it will unpack the vpk.
Drag the vpk file for this mod onto the vpk tool. Once the vpk is unpacked, go into the unpacked vpk folder and either delete the entire sound folder or delete the individual sounds.
After removing the sounds, you can then drag the vpk folder onto the vpk tool and it will repack the vpk. Move the repacked vpk back into your addons folder.