我今天要讲的是+topic. 我今天要讲的内容是关于 。。。。。 I guess I'd need more information to know how best to translate your meaning.

I know why you are stumped on this question. You are trying to translate the word "about." Many verbs in mandarin have the preposition built into their meaning so there may not be a need to translate "about" or other common English preposition. Example: 谈论 means to "talk about". This is why you don't have to translate the verb "is" in the sentence, "she is pretty." In Mandarin the adjective "pretty" has the verb "to be" built into it.

David's answer is awesome!! In addition to his reply, I have a better translation 今天我要谈论下我的家人，朋友以及我自己。 I think “谈论” is better than "讨论“ and ”介绍“ based on what you wanted to translate. 谈论 is talk about 讨论 discuss 介绍 introduce In your context, of course, 谈论is the best.

you can say 今天我要讲的是......或者我今天要讲的是......"今天"作为状语，可以用逗号分开，比如： 今天，我要讲的是..... 如果说完整句话：“今天我要讲的是一个故事。”我们来分析一下句子结构：今天（状语）+我（主语）+要（状语）+讲（谓）+的是（补语）+一个（定语）+故事（宾语）

今天我要谈谈怎样做到天天讲中文。Today, I will talk about how to speak Chinese every day. 我会与妳谈论健康，幸福与富足的。I will talk about health, happiness, and affluence with you.