了 is often considered one of the harder words in Mandarin, and its meaning is often translated in a number of different ways, such as “now” and “already”; and in reference to its other meaning, some think of it as a “past tense” word. These definitions may hurt intermediate students from advancing, as they really only work as a short-term solution to understanding a term that needs a lot of focused study to master. I will try here to help learners understand why these definitions may be holding them back.
The reason why we often translate this word as “now” and “already” is simply because there is no word that even comes close in meaning to it, and the same is true for its other meaning. It should be clearly noted that Mandarin does not have tense; many learners get confused because they don’t understand the difference between tense and aspect. 了 can be used in Mandarin as an aspect particle. Let’s look at the difference between tense and aspect and these two usages to understand what is going on.
**Tense & Aspect**
Tense expresses the time at which an event happens. For example:
I ate the sandwich
This is past tense, as it happened in the past; however, past tense does not inherently indicate a completed action. This is where aspect can be combined with tense in English to make more complicated combinations For example:
I was eating the sandwich
This is both past tense and expresses the continuous aspect, and this is called the past continuous in English. The continuous aspect expresses an on-going action, and it is not linked to any specific tense; thus, one could say “I was eating”, “I am eating”, and “I will be eating”. All of these express the continuous aspect.
In Mandarin, 了 can express what is known as the perfective aspect. This will be explored below under Meaning #2. While we won’t explore the other aspects that exist in Mandarin here, it will be mentioned that those are the following:
Delimitative: (expressed via reduplication)
Or, what many consider its “now” / ”already” meaning
In essence, this usage of the word really falls into a category that Li and Thompson in their book, which is listed below, call the “Currently Relevant State”, which they say means that “了 claims that a state of affairs has special current relevance with respect to some particular situation” (pg 240). This is a fancy way of saying that the word is bringing focus to something that is currently relevant.
下个月我就在日本了 / next month I’ll be in Japan
Li and Thompson say: “if a friend wants to see you next month, but you know you’ll be in Japan at that time … here the state of your being in Japan will be currently relevant to the” conversation. That is to say that by using this word, you are focusing on the fact that this sentence is in direct response to their question and that it is currently relevant information for this conversation.
Thus if we compare this with another,
电影开始了 / the movie is starting now / the movie started (already)
It could be said that you’re, say, texting this to someone because perhaps they haven’t yet arrived to the movie theater you’re at. It’s thus currently relevant to the situation of their arrival, so the word brings focus to that; this is why the sentence can be translated into English in multiple ways based on context. It’s not that the word changes meaning, it’s that the word’s meaning is solely to mark current relevance. It is up to the listener to understand why the sentence is relevant.
It is important to note here that the perfective 了 and the 了 that denotes current relevance are used differently. The former follows verbs and the latter is a sentence-final particle. There can obviously be confusion when the verb comes at the end and is followed by a 了, but learning to understand these sentences comes with time and experience with the underlying grammar.
Let’s take an easy example:
他睡了三个小时 / he slept for three hours.
This is an obvious example of the perfective 了 because we can see that not only does it follow the verb, but it also does not come at the end of the clause. It’s worth noting that the usage of 了 frequently collocates with phrases expressing limits of time, distance, or other ways of limiting a phrase. For example, 你高了一点 you’ve gotten a little taller.
Unfortunately there is just too much to cover about these two to truly do the word justice, but my favorite book on this topic is listed below and is my primary source. It has two whole chapters on this topic and hundreds of example sentences. Hopefully this has at least given clarity about this topic for many of you
Li, Charles N. & Thompson, Sandra A.. 2011. [Mandarin Chinese : a functional reference grammar](https://theswissbay.ch/pdf/Books/Linguistics/Mega%20linguistics%20pack/Sino-Tibetan/Mandarin%20Chinese%20-%20A%20Functional%20Reference%20Grammar%20%28Li%20%26%20Thompson%29.pdf). Univ. Of California Press.