여러분 의견 부탁드립니다. (발음 문제)
안녕하세요~

There is one thing I've always wondered about: pronunciation rules when there's a space between words, more specifically when ㄹ is followed by ㄴ.

For example, when you have ㅂ followed by ㅁ/ㄴ in a word, the ㅂ is pronounced ㅁ.
십만 [심만] - 눕는 [눔는]
Even when there's a space, every Korean person would follow the rule:
밥 먹다 [밤먹따] - 굽 높은 [굼노픈] 하이힐

Same for the rule that says ㄱ should be pronounced ㅇ before ㅁ/ㄴ.
No space: 악마 [앙마] - 먹는 [멍는]
With a space: 딱 맞아 [땅마자] - 꾹 누르다 [꿍누르다]

But when it comes to the rule that says ㄴ should be pronounced ㄹ before ㄹ, only some (50%) people follow the rule when there's a space. And even those 50% don't follow the rule sometimes.
No space: 잘나다 [잘라다] - 찰나 [찰라]
With a space: 반을 남기다 [바늘람기다/바늘남기다?] - 나를 놔 [나를롸/나를놔?]
What is the reason behind this?I believe [바늘람기다] and [나를롸] are the right pronunciations. Besides, it's smooth and easier to pronounce. ^^ I only gave two examples but this is so common, some more combinations I found in KPop songs are 늘 나의, 정말 너는, 다들 넘어가겠지, 집을 나서면, 정신을 놔 버릴, 사실 난, 한계를 넘어서, 매일 내가, etc.

Oh, while I'm at it, it's a bit the same with ㄹ before "compound" vowels (ㅑ ㅕ ㅛ ㅠ ㅒ ㅖ ㅘ ㅙ ㅚ ㅝ ㅞ ㅟ ㅢ).

With basic vowels (ㅏ ㅓ ㅗ ㅜ ㅡ ㅣ ㅐ ㅔ) everybody pronounces it the same.
No space: 돌아 [도라] - 들어 [드러] - 물오르다 [무로르다] - 일우 [이루]
발음 [바름] - 길이 [기리] - 갈애하다 [가래하다] - 물에 [무레]
With a space: ~ 줄 알아 [주라라] - 잘 어울려 [자러울려] - 늘 오는 [느로는] - 날 울게 [나룰게] - 널 잊으려 [너리즈려] - 날 애태우는 [나래태우는]Now the "compound" vowels.
No space: 불야성 [부랴성] - 길들여 [길드려] - 필요 [피료] - 발육 [바륙] - 불완전하다 [부롼전하다] - 불외하다 [부뢰/뤠하다] - 불원 [부뤈] - 무소불위 [무소부뤼] - 1위 [이뤼] - 불의 [부릐/리]
But when there's a space, for example: 함께하길 약속하다 - 문을 열어 - 날 용서해 - 널 유혹해 - 사랑을 얘기하다 - 정말 예뻐 - 정말 완벽해 - 나를 왜 - 날 외면해 - 널 원해 - 널 위해 - 너를 의심해.
Most (if not all) Koreans would pronounce those as [~길략~] - [무늘려러] - [날룡서해] - [널류호캐] - [사랑을럐기하다] - [정말례뻐] - [정말롼벼캐] - [나를뢔] - [날뢰면해] - [널뤈해] - [널뤼해] BUT [너르릐심해].
Why not [~기략~] - [무느려러] - [나룡서해] - [너류호캐] - [사랑으럐기하다] - [정마례뻐] - [정마롼벼캐] - [나르뢔] - [나뢰면해] - [너뤈해] - [너뤼해]? I again think these are correct pronunciations. ^^
I know there is no official rule about this, that's why I wanted to discuss this with anybody who'd like to give his opinion. ~Sorry it's so messy... I hate how italki doesn't allow us to put as much text as we want. Here's the result.

Question

여러분 의견 부탁드립니다. (발음 문제)
안녕하세요~
 
There is one thing I've always wondered about: pronunciation rules when there's a space between words, more specifically when ㄹ is followed by ㄴ.
 
For example, when you have ㅂ followed by ㅁ/ㄴ in a word, the ㅂ is pronounced ㅁ.
십만 [심만] - 눕는 [눔는]
Even when there's a space, every Korean person would follow the rule:
밥 먹다 [밤먹따] - 굽 높은 [굼노픈] 하이힐
 
Same for the rule that says ㄱ should be pronounced ㅇ before ㅁ/ㄴ.
No space: 악마 [앙마] - 먹는 [멍는]
With a space: 딱 맞아 [땅마자] - 꾹 누르다 [꿍누르다]
 
But when it comes to the rule that says ㄴ should be pronounced ㄹ before ㄹ, only some (50%) people follow the rule when there's a space. And even those 50% don't follow the rule sometimes.
No space: 잘나다 [잘라다] - 찰나 [찰라]
With a space: 반을 남기다 [바늘람기다/바늘남기다?] - 나를 놔 [나를롸/나를놔?]
What is the reason behind this?I believe [바늘람기다] and [나를롸] are the right pronunciations. Besides, it's smooth and easier to pronounce. ^^ I only gave two examples but this is so common, some more combinations I found in KPop songs are 늘 나의, 정말 너는, 다들 넘어가겠지, 집을 나서면, 정신을 놔 버릴, 사실 난, 한계를 넘어서, 매일 내가, etc.
 
Oh, while I'm at it, it's a bit the same with ㄹ before "compound" vowels (ㅑ ㅕ ㅛ ㅠ ㅒ ㅖ ㅘ ㅙ ㅚ ㅝ ㅞ ㅟ ㅢ).
 
With basic vowels (ㅏ ㅓ ㅗ ㅜ ㅡ ㅣ ㅐ ㅔ) everybody pronounces it the same.
No space: 돌아 [도라] - 들어 [드러] - 물오르다 [무로르다] - 일우 [이루]
발음 [바름] - 길이 [기리] - 갈애하다 [가래하다] - 물에 [무레]
With a space: ~ 줄 알아 [주라라] - 잘 어울려 [자러울려] - 늘 오는 [느로는] - 날 울게 [나룰게] - 널 잊으려 [너리즈려] - 날 애태우는 [나래태우는]Now the "compound" vowels.
No space: 불야성 [부랴성] - 길들여 [길드려] - 필요 [피료] - 발육 [바륙] - 불완전하다 [부롼전하다] - 불외하다 [부뢰/뤠하다] - 불원 [부뤈] - 무소불위 [무소부뤼] - 1위 [이뤼] - 불의 [부릐/리]
But when there's a space, for example: 함께하길 약속하다 - 문을 열어 - 날 용서해 - 널 유혹해 - 사랑을 얘기하다 - 정말 예뻐 - 정말 완벽해 - 나를 왜 - 날 외면해 - 널 원해 - 널 위해 - 너를 의심해.
Most (if not all) Koreans would pronounce those as [~길략~] - [무늘려러] - [날룡서해] - [널류호캐] - [사랑을럐기하다] - [정말례뻐] - [정말롼벼캐] - [나를뢔] - [날뢰면해] - [널뤈해] - [널뤼해] BUT [너르릐심해].
Why not [~기략~] - [무느려러] - [나룡서해] - [너류호캐] - [사랑으럐기하다] - [정마례뻐] - [정마롼벼캐] - [나르뢔] - [나뢰면해] - [너뤈해] - [너뤼해]? I again think these are correct pronunciations. ^^
I know there is no official rule about this, that's why I wanted to discuss this with anybody who'd like to give his opinion. ~Sorry it's so messy... I hate how italki doesn't allow us to put as much text as we want. Here's the result.

Answer

ㄴ 첨가 happens after ㄹ as well (열역학->[열녁학]), but in this case we end up with ㄴ after ㄹ, so the 유음화 rule of ㄴ-ㄹ changing to ㄹ-ㄹ(#1 above) kicks in. Hence 얼역학->[열녁학]->[열력학], 문을 열어->[무늘녀러]->[무늘려러], 날 용서해->[날뇽서해]->[날룡서해], etc.

This phenomenon seems consistent but nothing is 100% reliable, so sometimes one hears 문을 열어 pronounced as [무늘녀러] (but never [무느려러).  Also, ㄴ 첨가 doesn't happen with the [w] vowels as far as I know, so 정말 완벽해 is usually pronounced [정마롼벼캐].  Sometimes, ㄹ before these vowels can be a little difficult and unclear to pronounce, so 나를 왜 might sound like [나를 왜], [나르뢔], or even [나를뢔], but I believe [나르뢔] is the standard pronunciation.

So I would say the answer to the question "Why not [~기략~] - [무느려러] ..." is that generally the first sound of an independent word is pronounced with more stress and clarity than the reset of the syllables in it. It seems this is so strongly ingrained in our brain that we do it while seldom being conscious of it.

* Here's the link to the document I referenced:

http://www.kocw.net/home/search/kemView.do?kemId=444272 (click on "6차시" on the page).

"한국어 음운의 이해 - 6차시 <음성 음운의 결합>" - (2) 유음화 and (8) ㄴ 첨가

Answer

Here's what I found on the subject.

First, some clarifications.

In pronunciation involving two successive elements, the driving rule is usually not whether there is a space between them but whether the second part is an independently recognized word or concept.  Many compound words are pronounced as if there is a space between them.  For example 첫인상 is not [처신상] but [첟인상] because 인상 an independent concept.

Secondly, of the compound verbs, the [j] group (ㅣ ㅑ ㅕ ㅛ ㅠ ㅒ ㅖ) and [w]  group (ㅘ ㅙ ㅚ ㅝ ㅞ ㅟ) behave differently in many contexts.  I believe many of the pronunciation effects you mention only apply to the [j] group.

1) About ㄴ coming after ㄹ.

"유음화( 流音化 ): ᄂ 이 ᄅ 을 만나서 ᄅ 로 바뀌는 음운현상"

As you say 잘나다 is pronounced as [잘라다] and 반을 남기다 as [바늘람기다] as ㄴ coming after ㄹ changes to ㄹ regardless of the word boundary.  However, in songs the pronunciation might deviate from that of real life from various reasons.

2) Compound vowels (이, 야, 여, 요,...) after ㄹ.

"ㄴ 첨가: ᄂ 첨가는 복합어 나 파생어의 앞 말이 자음으로 끝나고 뒷말이 [i] 나 [j] 로 시작할 때 ᄂ 소 리가 첨가되는 음운현상이다"

Within a single word it is pronounced following the normal liaison.  So 불야성->[부랴성], 길들여->[길드려], 필요->[피료] - nothing special here.

On a word boundary (including within a compound word), the compound vowels (ㅣ ㅑ ㅕ ㅛ ㅠ ㅒ ㅖ) coming after a 받침 will undergo the "ㄴ 첨가 현상" (ㅇ becomes ㄴ).  So 먼 이웃->[먼니웃], 밭일->[밭닐]->[반닐](ㄴ 첨가, then the 자음동화 effect), 일본 요리->[일본뇨리], etc.

Answer

I don't think you should follow the rules. You already know how to pronounce some words. Practice makes perfect. I just try to speak like English natives, so I recommend you to repeat some words like Korean actors say in Korean dramas or movies.

Answer

actually there is official rule how to pronounciate .
and there is a book that explain about  what you are curious at
but i think you might not easy to find that book in your country  
so sad,,