The Last of Us Part II is an action-adventure game developed by Naughty Dog and published by Sony Interactive Entertainment. It's set five years after The Last of Us (2013) and, as its predecessor, focuses on storytelling and immersion into the post-apocalyptic United States. The outbreak was nearly 25 years ago and was caused by a mutated strain of the Cordyceps fungus, that can infect humans. It grows in the brain and slowly starts to take control over the host, turning it into a zombie-esk creature, called the infected.

It's noticeable that sound design was a key part in the development of The Last of Us Part II. It is strongly focused on immersion and realism. Every little detail has its distinct sound, but still the audio is always focused on the player and plays in an almost theatrical way around the player's actions, in a responsive manner.

Stealth is a big part of the gameplay and this is well represented in the sound of all enemies, most enemy types have their distinct sounds, making them easily recognizable without having to see them.

Most of the surviving humans have rallied into smaller or bigger groups, even founded settlements and small towns. During the game you meet multiple of them and most of the time they react hostile to outsiders. Their barks are particularly interesting in this game, since they often talk to each other about events in the world or their specific group. Like everything else in the game, they are particularly responsive to the players actions. For example, calling out dead members by their name or surrender to the player, if they realize they have no chance. One group is especially interesting, the Seraphites (Scars). They communicate manly with different whistle sounds. And with confronting them more and more, you start to learn what the different sounds mean.

For example, the call and the answer:

There are different stages of the Cordyceps brain infection (abbreviated as CBI) and they got categorized into different enemy types. Each one has its distinct attributes and behavior, which also get represented in the sounds they make.

Runner
The earlier stage CBI infection. The sounds they make still sound like coming from a human, and the difference of male and female specimen is quite audible.

Stalker
A more advanced stage, still a bit human sounding. The difference between female and male stalkers is less audible.

Clicker
Advanced stage, there isn't much human left in their sounds. Female and male specimen sound basically the same. Clickers have lost their eyesight and orientate themselves using clicking sounds.

Shambler
Very advanced stage, making more creature than human sounds, with lots of grunts and gurgles. Although there still is some human resemblance in the breathing.

Bloater
Another very advanced stage, making even deeper creature-like grunts than the Shamblers.

RatKing
The most advanced stage currently known, a super-organism composed of multiple stalkers, clickers and a bloater. They mostly make Clicker sounds, but more aggressive than normal CLickers.