Saying and hearing

听说 (tīng shuō) is listen plus speak. It means I hear that or apparently, and it is one of the most useful things in this session.

听说他要走了 is I hear he is leaving. There is no need for a subject or a source; the word itself carries the sense of secondhand information.

This is Mandarin's dominant habit: take two related characters and put them together to make something more specific than either. Once you notice it, vocabulary stops being a list and starts being combinable.

The four ways to understand

懂 (dǒng) is to understand, the plain everyday verb. 我不懂 is I do not get it.

明白 (míng bái) is bright plus white, and it means to be clear about something. 我明白了 is ah, I see - the moment of clarity.

了解 (liǎo jiě) is to know about, to be familiar with. It is used for understanding a situation or a person over time.

理解 (lǐ jiě) is to comprehend, more analytical and slightly formal, the word for understanding an argument or a reason.

English has understand, see, know about and comprehend for roughly the same four jobs, so the concepts are not foreign. Only the mapping has to be learned.

说 and 讲 and 谈

说 (shuō) is to say, the default. 讲 (jiǎng) is to speak or to tell, slightly more deliberate, and it is what a lecturer does. 谈 (tán) is to discuss or talk over, always with someone.

You cannot 谈 alone, and you cannot 说 a lecture.

问题 is a problem and a question

问题 (wèn tí) is built from 问 (wèn), to ask. It means a question, and it also means a problem.

没问题 is no problem. 有问题 can be there is a question or there is a problem, and only context tells you which, which occasionally makes for a genuinely ambiguous sentence in a meeting.

打电话

打电话 (dǎ diàn huà) is to make a phone call, and the verb 打 (dǎ) means to hit. You hit a telephone. 打 is one of the most overworked verbs in the language: it opens, it plays, it makes, it types, and it fights.