Translation guide
Describes large numbers of people, animals, or insects moving or gathering together. Japanese uses different expressions depending on what is swarming and the nuance (neutral, negative, or overwhelming).
Describe insects, bugs, or small creatures moving or gathering in large groups.
General phrase meaning 'in a swarm/flock/herd'. Works for insects, birds, fish, etc. Neutral tone.
蚊が群れをなして飛んでいる。
Mosquitoes are flying around in swarms.
Onomatopoeic adverb describing many small creatures (insects, worms, etc.) wriggling or swarming in an unpleasant way. Often negative nuance.
ゴキブリがうじゃうじゃいる。
There are cockroaches swarming everywhere.
Onomatopoeia for many small things moving in a swarm, often used for insects or small creatures. Can sound slightly cute or creepy depending on context.
アリがわらわらと出てきた。
Ants came out in swarms.
Describe large numbers of people gathering or moving in a crowded, often chaotic manner.
Noun/adverb meaning 'a large number of people'. Neutral and common.
観光客が大勢押し寄せた。
Tourists came in swarms.
Onomatopoeic adverb for people or animals moving in a continuous line or swarm. Often implies a somewhat disorderly crowd.
Verb meaning 'to swarm/crowd around'. Often used for people or animals gathering around something.
Adverb meaning 'in swarms/in great numbers', often used for people or things. Colloquial and slightly old-fashioned.
人がわんさか集まってきた。
People gathered in swarms.
Express that something appears or occurs in huge, often overwhelming numbers (not necessarily living).
Adverb meaning 'in large quantities'. Neutral and widely applicable.
苦情が大量に届いた。
Complaints arrived in swarms.
Onomatopoeic adverb for a sudden rush or flood of people/things. Emphasizes the suddenness.
注文がどっと殺到した。
Orders came flooding in (in swarms).
群れ (mure) is a noun for a group of animals/insects. 大勢 (ōzei) is specifically for people. 大量 (tairyō) is for quantities of things. Use 群れをなして for 'in swarms' of creatures, 大勢 for people, and 大量に for inanimate things.
English 'in swarms' can be used metaphorically for non-living things (e.g., 'emails in swarms'). Japanese often uses 大量に (in large quantities) or 殺到する (to rush/flood) instead of insect-related words. Using 群れ for emails sounds unnatural.
人がぞろぞろと駅から出てきた。
People came out of the station in swarms.
子どもたちがアイスクリーム屋に群がった。
Children swarmed around the ice cream shop.