Hi Oscar! At their base definitions, they're the same thing： 说 means "speak" and 说话 means "speak dialogue," but obviously, when you're speaking, you're already speaking dialogue. However, like so many terms in Chinese, they're used differently in different situations. 说 is used when referring to speaking specifically about something, whereas 说话 is used when referring to speaking in general. Here's an example: ”你明明知道！她在哪里？快说！“ This means "You clearly know! Where is she? Speak up!" In this situation, the speaker wants the listener to tell him/her something specific (where the woman he/she is looking for is), so 说 is used. "他已经三岁了，为什么还不会说话？“ This means "He's already three-years-old; why doesn't he know how to speak yet?" In this situation, the speaker is wondering not about something specific that the boy is saying, but about why the boy cannot speak in general yet despite his age. I hope this helps. Please let me know if you have any further questions.

说 is a verb, which means to speak or say. 话 is a noun, and means speech or words. 说 often takes a direct object, the most generic of which is "话。” That's why you often see them together. It's no different from, say "跳舞” or ”睡觉” In both examples, the first character is the verb, and the second is its direct object.

我认为“说话”译成talking about sth.并不准确，说话也是有不同含义的。比如：你们别说话了。这里的说话并不关心“about sth”仅仅表示不要发出声音来，不聊天之类的意思。“春节说话就到了”这里的“说话”更与about sth.无关了。

Technically, “说” means to talk and "说话" means "talking about sth". So the sentence "What are they talking about?" can be translated into "他们在说什么？" And "They are talking." can be translated into “他们在说话。” As a native speaker I think we normally add a noun after a verb, at least for most of the time; so in this case, if it's not a question, you have to use the word "说话". Like when people talking about the plan for tomorrow or what to eat for dinner, we say "他们在说明天的计划" and "他们在说晚饭吃什么". So it's "说" plus a noun. But sometimes in reality, when we try to stop people from talking, we say "你们别说了" as well. We ignore "话" because we taciturnly acknowledge the content of their conversation. But still "你们别说话了" is correct under this circumstance. Good luck learning Chinese!

Technically, “说” means to talk and "说话" means "talking about sth". So the sentence "What are they talking about?" can be translated into "他们在说什么？" And "They are talking." can be translated into “他们在说话。” As a native speaker I think we normally add a noun after a verb, at least for most of the time; so in this case, if it's not a question, you have to use the word "说话". Like when people talking about the plan for tomorrow or what to eat for dinner, we say "他们在说明天的计划" and "他们在说晚饭吃什么". So it's "说" plus a noun. But sometimes in reality, when we try to stop people from talking, we say "你们别说了" as well. We ignore "话" because we taciturnly acknowledge the content of their conversation. But still "你们别说话了" is correct under this circumstance. Good luck learning Chinese!