Learn Hardcore Japanese: zatuon ga aru to, kaiwa ga kikoemasen. - When there is noise, I can’t hear the conversation.

In this sentence, が is the subject marker. It indicates that 雑音 (noise) is what “exists” (via the verb ある). So 雑音がある literally means “there is noise.”

Why is ある used instead of いる?

Japanese distinguishes animate vs. inanimate existence. You use いる for animate beings (people, animals) and ある for inanimate objects or abstract things. Since 雑音 is not alive, you use ある.

What role does the conditional と play in 雑音があると、会話が聞こえません?

Here, と expresses a general condition: “whenever/if the first clause is true, the second clause naturally follows.” So 雑音があると means “if/whenever there is noise, …”

Why is 聞こえません used instead of 聞きません?

聞こえる is an intransitive verb meaning “to be audible” (i.e. sound reaches your ears on its own). 聞く is transitive, meaning “to listen” or “to hear” (actively). Because you’re saying the sound itself isn’t reaching you, you use 聞こえません.

Why does 会話 take が in 会話が聞こえません rather than を?

With intransitive verbs like 聞こえる, the thing that exists or happens (here, 会話 becoming audible) is marked by が. You would only use を with transitive verbs where you actively do something to the object.

Why is the polite negative 聞こえません used instead of the plain 聞こえない?

聞こえません is the polite (masu-stem) negative form; 聞こえない is the plain form. The example sentence is in polite style, so it uses 聞こえません.

Can I replace と with から in this sentence?

Yes—you could say 雑音があるから会話が聞こえません, meaning “because there is noise, I can’t hear the conversation.” However, と conveys a more automatic/whenever-this-happens result, while から states a direct cause-and-effect reason.

Is the comma after と necessary?

No, it’s optional. Writers often insert a comma to clarify the break between the conditional clause and the result, but the sentence is grammatically correct without it.