I find LingoDeer much better but I still use Duolingo sometimes :) LingoDeer explains grammar really well.
The reason they dont is so that you get used to the word structure which is why you do the hangul alphabet lesson first. It will help with reading korean writing out loud more fluently
I had a fluent korean speaker help me pronounce the word correctly, and the end of the word in this audio doesnt seem correct. It sounds like nam-jah-day in the recording, but the person who showed me how to pronounce it said it like nam-jah-doo. I dont really like the audio quality in this app :/
It is pronounced "L", Koreans don't let air through at the last letter. Ex. 집: People would pronounce the b, how koreans do it is that they keep their mouth closed on the last letter instead of letting air escape to make the sounds clear. When you would say the word "Mask" (Eng) you also say a very short "eh/eu" at the end because you have to pronounce the k sharply, if you would take that away your mouth would be closed and you wouldn't hear the k. That's why english words in hangul often have an excessive amount of 으 in between parts or at the end of words. 치즈 = cheese (note the ㅡ). Hope this helped.