Learn Hardcore Japanese: kyou ha atui desu kara, aisu wo tabemasu.

は marks the topic of the sentence—what you’re talking about—so 今日 (today) is set up as the topic (“As for today…”). が would mark the subject, focusing on “today” as new or contrastive information (“It is today that is hot”), which changes the nuance.

Why is は pronounced わ here instead of は?

When the hiragana は functions as a topic particle, its pronunciation shifts to わ. When it’s part of a word (not as a particle), it stays ha.

What role does です play after the adjective 暑い?

です is the polite copula. After an い-adjective like 暑い, adding です makes the statement polite: 暑い → “hot,” 暑いです → “(it’s) hot (polite).”

Why is から used here, and what does it mean?

から attaches to a clause to mean “because” or “so.” The first clause gives the reason: 今日は暑いです (“since today is hot”), and から links to the main action: アイスを食べます (“I will eat ice cream”).

Could I use ので instead of から? What’s the difference?

Yes, ので also means “because” and is slightly more formal or indicates a softer cause-effect. With ので you’d say 今日は暑いですので、アイスを食べます。 But から is more direct and common in everyday speech.

What does アイス refer to here? Why not アイスクリーム?

アイス is a clipped form of アイスクリーム often used in casual contexts. It can also mean ice (frozen dessert) or ice pops, but here it implies ice cream generally.

Why is を placed after アイス?

を marks アイス as the direct object of the verb 食べます—what you’re eating.

Why is the verb 食べます in this polite form, not 食べる or 食べた?

食べます is the non-past polite form (“will eat” or “eat”).

食べる is plain non-past (“eat”).
食べた is plain past (“ate”).
食べました would be polite past (“ate,” polite).

Can you drop です after 暑い in casual conversation?

Yes. In casual speech you can say 今日は暑いから、アイスを食べる。 Dropping です and using the plain verb 食べる makes it less formal.

Is the word order always topic – comment – reason – action in Japanese?

Japanese is generally SOV (Subject-Object-Verb) with topics up front, but the order of topic, reason, and action can be flexible. Particles like は, を, and から tell you each part’s role, so you could sometimes rearrange clauses, though natural speech often follows this pattern.