In short

When a cause produces a bad or unintended result, Korean sets aside the neutral “because” words from lesson 28 and reaches for a set of blame-and-mishap connectors. -느라고 (-neurago) = too busy doing X to manage Y - same person, usually an excuse. -는 바람에 (-neun barame) = and then, out of nowhere, X spoiled it. -(으)ㄴ/는 탓에 (-(eu)n/neun tase) = it happened because of X, and that is X’s fault. -(으)ㄹ까 봐 (-(eu)lkka bwa) = I did it for fear that X might happen.

The rule

Step 1 - -느라고: too busy doing X to do Y (same subject, an excuse)

Attach -느라고 straight onto a verb stem - never an adjective, and with no tense marker (no -았/었-). The first clause is what occupied you; the second states the cost you paid for it, almost always a failure or a negative: 공부하느라고 못 갔어요 (gongbuhaneurago mot gasseoyo, I couldn’t go because I was studying). Three hard limits:

• Same subject in both clauses - one person does X and pays for it.
• Verb only, and present form only (put no -았/었- on 느라고).
• No command or suggestion may follow - a question about the outcome is fine (늦었어요?), but a plain statement is the normal close.

A ㄹ-stem drops its ㄹ before ㄴ: 만들다 -> 만드느라고 (mandeuneurago).

Step 2 - -는 바람에: a sudden external mishap ruins things

Build the -는 modifier form of a verb and add 바람에: 비가 오는 바람에 늦었어요 (biga oneun barame neujeosseoyo, it suddenly rained, so I was late). This one is for an unexpected, external cause with a negative outcome, and the main clause is normally past tense. Unlike 느라고 the subject is free - the cause is usually somebody or something else. 바람 literally means “wind”: think of a gust that knocks your plan over.

Step 3 - -(으)ㄴ/는 탓에 / N 탓에 / 탓으로: assigning blame

탓 means “fault.” Use the modifier that fits the clause, then add 탓에: a completed cause takes the past modifier -(으)ㄴ 탓에 (준비를 안 한 탓에, junbireul an han tase, because I didn’t prepare); an ongoing habit takes -는 탓에; an adjective takes -(으)ㄴ 탓에 (추운 탓에, chuun tase, because it’s cold). After a bare noun use N 탓에 or N 탓으로: 날씨 탓에 (nalssi tase, because of the weather). It always points a finger, so the result is negative. Its positive twin is -(으)ㄴ 덕분에 / N 덕분에 (deokbune, thanks to) - swap 탓 for 덕분 when the outcome is good.

Step 4 - -(으)ㄹ까 봐(서): acting out of worry

Add -(으)ㄹ까 봐 (optionally -(으)ㄹ까 봐서) to a verb or adjective stem. The first clause is a feared outcome; the main clause is the precaution you take against it: 늦을까 봐 뛰었어요 (neujeulkka bwa ttwieosseoyo, I ran because I was afraid I’d be late). Read it as in case / for fear that. Unlike the other three, this one does take -았/었- when the feared thing may already have happened: 아이가 감기에 걸렸을까 봐 걱정했어요 (aiga gamgie geollyeosseulkka bwa geokjeonghaesseoyo, I was worried the child might have caught a cold). The subject of the worry clause is free - it is often somebody else. 봐 is the auxiliary verb 보다, so it always keeps its space.

Step 5 - -는 통에: the colloquial “commotion” variant

-는 통에 works like 바람에 but carries an extra nuance of noise, chaos, or being caught up in a fuss: 옆집이 시끄러운 통에 못 잤어요 (yeopjibi sikkeureoun tonge mot jasseoyo, I couldn’t sleep because next door was so noisy). A verb takes -는 통에; an adjective takes -(으)ㄴ 통에, which is why 시끄럽다 shows up here as 시끄러운 통에. It is casual and spoken - in writing prefer 바람에 or 탓에.

Forms & patterns

Verb-attaching mishap connectors (-느라고 takes the plain stem; 바람에 / 통에 take the -는 modifier):

탓에 (blame) and -(으)ㄹ까 봐 (worry) - pick the form by what precedes:

How the adverse causes differ from the neutral three (lesson 28):

Examples

Common mistakes

• 공부했느라고 못 갔어요. (Gongbuhaenneurago mot gasseoyo.) -> 공부하느라고 못 갔어요. (Gongbuhaneurago mot gasseoyo.) - -느라고 never carries -았/었-; leave the stem in its plain present form.
• 동생이 우느라고 제가 못 잤어요. (Dongsaengi uneurago jega mot jasseoyo.) -> 동생이 우는 바람에 못 잤어요. (Dongsaengi uneun barame mot jasseoyo.) - -느라고 demands the same subject; when someone else’s action is the cause, use -는 바람에.
• 열심히 공부하는 바람에 시험을 잘 봤어요. (Yeolsimhi gongbuhaneun barame siheomeul jal bwasseoyo.) -> 열심히 공부한 덕분에 시험을 잘 봤어요. (Yeolsimhi gongbuhan deokbune siheomeul jal bwasseoyo.) - 바람에 marks a bad outcome; for a good result use -(으)ㄴ 덕분에 (thanks to).
• 비가 오는 바람에 우산 가져가세요. (Biga oneun barame usan gajeogaseyo.) -> 비가 오니까 우산 가져가세요. (Biga onikka usan gajeogaseyo.) - none of these adverse-cause connectors allows a command after them; switch to -(으)니까 when an imperative follows.
• 늦을까봐 뛰었어요. (Neujeulkkabwa ttwieosseoyo.) -> 늦을까 봐 뛰었어요. (Neujeulkka bwa ttwieosseoyo.) - 봐 is the auxiliary 보다 and takes a space; write -(으)ㄹ까 봐, not -(으)ㄹ까봐.

Tips

• -느라고 = “too busy to.” One person, present-form clause, and the payoff is always a loss (못 갔어요, 늦었어요, 피곤해요). If the two clauses have different subjects, you want 바람에, not 느라고.
• Let the outcome pick the word. Bad and blamed -> 탓에 (탓 = “fault”); bad and sudden -> 바람에 (바람 = “wind”); good -> 덕분에 (“thanks to”). Same slot after a modifier, opposite polarity.
• -(으)ㄹ까 봐 is preventive. You do the main action to head off the feared one, so it loves verbs of precaution: 뛰다 (run), 서두르다 (hurry), 조심하다 (be careful). Translate it as in case or for fear that.
• 통에 is speech only. It adds a whiff of commotion and stays out of formal writing - reach for 바람에 or 탓에 on paper.