That's not how Japanese works. Yes Japanese uses Chinese characters that's only a subset of Japanese. Japanese sentences are typically a bit longer than English in terms of syllables and written length - their main reduction technique at the language level is omission, rarely efficiency improvement.

- Why's it so hot today? = 6 syllables

- Nande konna ni atsui no kyou? = 10 syllables (spoken colloquially)

What about written length? You can see the Japanese sentence is a little longer here (when the English uses a non-monospaced font). It's also enough to demonstrates the why using kanji doesn't always provide the huge reduction/compression that you're expecting.

- Why's it so hot today?

- なんでこんなに暑いの今日？

> Japanese sentences are typically a bit longer than English in terms of syllables and written length?

Do you understand than 1 kana represents 1 syllable? They are BY DEFINITION, more concise than Latin letters.

Wow thanks! I didn't understand that despite being able to read and write Japanese! Sarcasm aside you don't seem to have a very deep understanding so maybe you should be a bit nicer when expressing your opinion.

> 1 kana represents 1 syllable

ちゅ <-- 2 kana, 1 syllable

> BY DEFINITION, more concise than Latin letters

smash <-- 1 syllable, 5 latin letters, ~3 kana in length スマッシュ <-- 5 kana

Why’s it so hot today?

何でこんなに暑いの今日？

Where in the US are you from?

出身は米国の何処ですか?

Japanese sentences are usually shorter than the english translation.

For paid translations, English likes to charge by the word, whereas Japanese charges by the character. The rule of thumb for conversion is 2 JP characters --> 1 English word i.e. translating a 1000 character JP document you'll expect about 500 EN words at the end.

I speak Mandarin Chinese. They are kind of similar.

今天怎麼這麼熱？

美國那來的？