Thank you. “Do you speak Chinese” and “Can you speak Chinese” pretty much means the same thing in English.
In other lessons, DL has the following:
¿Sabes cocinar? --- Can you cook?
¿Sabes nadar bien? --- Can you swim well?
¿Sabes nadar? --- Can you swim?
Ellos saben contar --- They can count
Ustedes saben escribir --- You can write
There are hundreds of Chinese languages, but the Chinese people themselves are to blame for this conflation: they typically regard all Chinese languages as local dialects (and the government encourages this) mainly out of nationalism, despite their mutual unintelligibility. This is why they can all be called chino.
"Do you know to use...?" significa que “¿sabe lo que DEBE usar...?”
"Do you know HOW to use...?” significa que “Está consciente de cómo usar ...?”
"Do you know to use ...?" means “Do you know that you MUST/SHOULD use ...?”
"Do you know how to use...?” means “Do you know the manner in which to use ...?”
That works in English, but not so well in Spanish. If you ask "¿Usted habla chino?", it sounds surprised, like you just witnessed the person speaking Chinese and you didn't know that they have the ability. (Or if you didn't know what language it was.)
You can say either "¿Sabe hablar chino?" or "¿Puede hablar chino?" when asking about their abilities.
I wouldn't translate ustedes with "all of you". "All of you" focuses on the fact that every single person of that group has the ability, while the original sentence just very generally probes whether the group, at large, can speak the language.
"All of you" is better expressed as "todos ustedes".
This sentence isn't technical because Chinese people themselves and their government conflate all the various Chinese languages as a single "language". This isn't the problem of Western linguists, or Duolingo, by any means. That being said, "Chinese" typically refers to Standard Chinese, or the Beijing dialect of Mandarin.
If you are learning Chinese be wary of the Duolingo Chinese tree. Even though it is out of beta it is a patience warping trial. The translations are excrutiatingly obtuse. YOU'VE BEEN WARNED!!!