the meaning of "같아"?
for example: "다른 세상 사람 같아" can't you easily use "다른 세상 사람" without the "같아"? explanation, please!
In Naver Dictionary 같다 (the basic form of 같아) translates as follows:
①same,identical, equal, equivalent, common
②similar, like, alike
So basically what niskiqwun already said: in this case it means "to be like something". Meaning that without it the sentence would not only lack the word "like" but also the verb "to be" that makes it a sentence in the first place. What is left is just a noun.
다른 = different
세상 = world
다른 세상 사람 = person from the different world
같아 = like
그들은 다른 세상 사람 같아 = They are like people from the different world.
Hope you pay extra attention in familiarizing yourself with expressions such as 같아, 같아요, 같다 since they are used extremely frequently in daily conversations as well as songs. :D
FYI, there seems to be an army of Spanish native speakers uploading various contents on youtube with both Korean romanization and Spanish subtitles. Hope you also take advantage of such to get your ears used to the various pronunciations.