The particle -을/를 is one of the most basic particles in Korean grammar a Korean language learner has to master. If you do not know how to use it and what it signifies, understanding even basic Korean sentences becomes almost impossible. So let’s make sure you truly understand this particle
The particle -을/를 is known as the object particle because it indicates the direct object in a Korean. That is why many verbs will require you to use this particle. However, in spoken Korean, people tend to omit the particle. Typically, the context is enough to make clear what the direct object in a sentence is. But, when it isn’t you have to use it.
So-called 하다 verbs (Sino-Korean verbs or 한자어) are actually the result of shorting the forms of NOUN + 을/를 하다, like 공부를 하다. However, typically the -을/를 is omitted and the words written as one single word, like 공부하다. This is important to remember because sometimes they are split up into two words.
Do keep in mind that 좋아하다 and 싫어하다 cannot be split in this fashion.
가: 뭐 하고 싶에요?
나: 수영하러 바다에 가고 싶어요.
A: What do you want to do?
B: I want to go to the beach to swim.
How To Use
The particle -을/를, like the other two basic particles -은/는 and -이/가, follows the ‘batchim/no batchim’ rule in Korean. This means that you use -을 when a noun ends in a batchim (ends in a consonant). But, when it ends in no batchim (a vowel), you use -를. After that, there is little else to do.
The question word 무엇 (what) is a rather peculiar word in Korean. This word can be shortened to 뭐 and if you want to add -을/를 to that shortened for,뭘 is typically used instead of 뭐를. Although, simply using 뭐 is done often in conversations.