Learn Hardcore Japanese: tenin ha 「sityakusitu ha uketuke no yoko ni arimasu」 to iimasita. - The clerk said, “The fitting room is next to the reception desk.”

は is the topic marker. Here it introduces who is speaking—“As for the shop assistant…” If you used が, you’d simply mark “the shop assistant” as an unintroduced subject, which sounds more like you’re focusing on identifying them rather than on what they said.

Why does 試着室 also take は inside the quote?

Inside the quotation the speaker is setting 試着室 (“the fitting room”) as the topic of their statement. In Japanese you can have a topic in your main clause (店員は) and an independent topic in a quoted clause (試着室は).

What does 受付の横 mean, and how does の work here?

受付の横 literally means “the side of the reception desk.” The particle の links 受付 (“reception desk”) to 横 (“side”), forming a noun phrase [reception desk + ’s side].

Why is に used after 横 in 横にあります?

Verbs of existence like ある/います require に to indicate location. So 横にあります means “exists at the side” (i.e. “is located next to”).

Why is the verb あります used instead of います?

あります is used for inanimate objects and places. 試着室 (a room) is inanimate, so we use あります. います is reserved for animate beings (people, animals).

What role does と play in と言いました?

The particle と marks the end of quoted speech. Xと言いました means “(someone) said X.” Everything before と is treated as the quoted content.

Why is 言いました in the past tense, while あります inside the quote stays non-past?

Japanese reporting verbs (here 言いました, “said”) take past to indicate the act of speaking happened already. The content of that speech remains in its original tense—so the fitting room “is” next to the reception, not “was.”

What’s the difference between 横 and 隣 when describing location?

横 (“side”) implies a general adjacent area, not necessarily immediately touching. 隣 (“next to”) usually implies direct adjacency, like sharing a wall in buildings. In everyday speech for a shop you might hear either, but 隣 feels a bit more strictly “right beside.”