좀 (jom) is written as a shortening of 조금 (jogeum, a little), and in most sentences it has nothing to do with quantity. It is a softener. 좀 도와주세요 does not mean help me a little. It means please help me.
Korean requests sound blunt without something taking the edge off, and 좀 is the cheapest available cushion. One syllable, drops in almost anywhere, and its literal meaning is faint enough that nobody hears an actual amount.
Romanized jom, sometimes jum or chom. The initial ㅈ is unaspirated, so jom is the better match.
Usage
좀 도와주세요 (jom dowajuseyo) = could you help me
물 좀 주세요 (mul jom juseyo) = could I have some water
No quantity implied. Asking for a little water would be strange.
저기 좀 여쭤볼게요 (jeogi jom yeojjuobolgeyo) = excuse me, could I ask something
Stacking softeners. 저기 and 좀 and the humble verb, all doing the same job.
좀 이따가 (jom ittaga) = in a bit
Here it genuinely is about amount, of time.
좀 비싸네요 (jom bissaneyo) = it’s a bit expensive
And here it is hedging an opinion, which is a third job.
The three jobs
It helps to separate them, because learners tend to learn one and use it everywhere.
Softening a request. This is the big one. 주세요 alone is grammatically polite and can still land as an order. 좀 주세요 sounds like a person asking.
Hedging a statement. 좀 어려워요 means it is difficult, with the 좀 lowering the confidence rather than the difficulty. Korean conversation hedges opinions heavily, and a bare 어려워요 can sound like you are shutting down a topic.
Actual quantity. 좀 더 (jom deo) is a little more, 좀 있다가 is in a while. This use survives and is a minority of what you hear.
좀 has a sharp version
The same syllable can be pointed, and the difference is stress and position.
When 좀 lands after a verb in a command, it stops softening and starts pressing. 그만 좀 해 carries visible irritation. 조용히 좀 해주세요 is a request with an edge on it, the kind of thing said to a noisy table.
The tell is that the 좀 has moved. In 좀 도와주세요 it sits before the verb and cushions. In 조용히 좀 해주세요 it sits between the adverb and the verb and functions as pressure. The literal meaning is the same and the effect is opposite.
This is the main reason to be careful with 좀 while your instincts are still forming. The softening use is safe. The pressing use is easy to produce by accident.
좀 vs 조금 vs 잠깐
조금 is the full form and it stays literal. 조금만 주세요 means give me only a little, and it is about amount. If you actually want to specify a small quantity, use 조금 and the ambiguity disappears.
잠깐 (jamkkan) means briefly, for a moment. 잠깐만요 is the standard way to say hold on. Learners sometimes reach for 좀만요, which is not idiomatic.
So the split is roughly: 조금 for amounts, 잠깐 for short durations, 좀 for everything social.
Formal settings
좀 is fine in polite speech. It appears with 요 endings and with 습니다 endings, in shops, offices, and service situations, and it does not read as slangy. This makes it unusual in this series, most of which is chat vocabulary.
Where it does not work is formal writing. Documents, reports, and academic prose do not hedge with 좀, and they use 다소 (daso) or 약간 (yakgan) instead, both meaning somewhat. Seeing 좀 in a written report would look like speech leaking in.
The other limit is that softening does not fix an inappropriate request. 좀 makes a reasonable ask sound gentler. It does not make an unreasonable one acceptable, and stacking it does not help.
좀 turns up in nearly every spoken request in Korean, and its absence is more audible than its presence.