Indicates a slow but gentle and natural pace or action
When to use
walking pace, speaking manner, driving style
The nuance
Used when the speed of an action or movement is slow yet gentle and careful.
천천히 (cheon-cheon-hi, cheoncheonhi) · 느리게 (neu-ri-ge, neurige) · 서서히 (seo-seo-hi, seoseohi)
천천히 expresses a gentle, natural slowness; 느리게 states an objectively slow speed; 서서히 describes gradual, step-by-step changes over time.

One lane per word — no nested boxes, just the gist.
Indicates a slow but gentle and natural pace or action
When to use
walking pace, speaking manner, driving style
The nuance
Used when the speed of an action or movement is slow yet gentle and careful.
Used to emphasize that the speed is objectively slow
When to use
machine operation speed, reaction speed, time measurement
The nuance
Used to emphasize or compare the fact that something is slow in speed.
Used when a change or progress happens gradually and step-by-step
When to use
weather change, emotional change, state change
The nuance
Used for situations where something changes or progresses little by little over time.
그는 천천히 걸었다.
geu-neun cheon-cheon-hi geol-eoss-da., geu neun cheon cheon hi geol eoss da.
Describes walking at a slow, gentle, and natural pace, so 천천히 is appropriate.
그는 느리게 걸었다.
geu-neun neu-ri-ge geol-eoss-da., geu neun neu ri ge geol eoss da.
For walking, using 느리게 to objectively state slowness is unnatural; 천천히 is preferred.
기계가 느리게 작동한다.
gi-gye-ga neu-ri-ge jak-dong-han-da., gi gye ga neu ri ge jak dong han da.
느리게 correctly emphasizes the objectively slow operation speed of a machine.
기계가 천천히 작동한다.
gi-gye-ga cheon-cheon-hi jak-dong-han-da., gi gye ga cheon cheon hi jak dong han da.
천천히 implies gentle natural movement, which doesn't fit machine operation.
날씨가 서서히 추워진다.
nal-ssi-ga seo-seo-hi chu-wo-jin-da., nal ssi ga seo seo hi chu wo jin da.
서서히 fits gradual, step-by-step changes like weather getting colder.
날씨가 느리게 추워진다.
nal-ssi-ga neu-ri-ge chu-wo-jin-da., nal ssi ga neu ri ge chu wo jin da.
느리게 emphasizes speed, not gradual change; 서서히 is correct for gradual changes.
그는 서서히 감정을 드러냈다.
geu-neun seo-seo-hi gam-jeong-eul deu-reo-naess-da., geu neun seo seo hi gam jeong eul deu reo naess da.
서서히 is used when emotions reveal themselves gradually.
그는 천천히 감정을 드러냈다.
geu-neun cheon-cheon-hi gam-jeong-eul deu-reo-naess-da., geu neun cheon cheon hi gam jeong eul deu reo naess da.
천천히 suits action speed, not gradual emotional changes.
Which adverb fits when walking speed is gentle and natural?
Which is appropriate when machine speed is objectively slow?
Which adverb to use for gradual emotional change?