I listen to their talks carefully and I talk them compliments! Let’s have a sing. -> Is ‘sing’ written as a verb here?

Hi, Minju! Thank you for the great questions. I hope the explanations are clear. If not, let us discuss more in the class. See you!

--Teacher Anji

I listen to their talks carefully and I talk them compliments!

>> I listen to what they say carefully, and give them compliments. 

Let’s have a sing.
>> Is ‘sing’ written as a verb here?

Answer: The sentence itself is incorrect. It should be:

>> Let's sing. (verb)

OR >> Let's sing a song. (verb)

But if we use it as a gerund or infinitives, it can be used as a noun.

example: 

>> I love to sing. ( to sing = infinitive, and the object of the sentence)

>> I loving singing. (singing = gerund, and the object of the sentence)

>> To sing Kpop songs is my hobby. ( to sing = infinitive, and the subject of the sentence)

>> Singing Kpop songs is my hobby. (singing = gerund, and the subject of the sentence)