Translation guide
How to express that something or someone becomes vulgar, crude, or loses refinement in Japanese.
Describing a person, speech, or manner that becomes crude, unrefined, or lacking in class.
The most common and neutral way to say 'become vulgar' for people, speech, or behavior. 下品 means 'vulgar' or 'crude', and になる means 'to become'.
He becomes vulgar when he drinks alcohol.
The conversation suddenly became vulgar because of that joke.
Literally 'lose refinement/elegance'. Often used when something loses its classy quality.
After becoming rich, he lost all refinement.
Means 'become vulgar' in the sense of becoming worldly, common, or unrefined. Often used for tastes or style.
Recent fashion has become vulgar/common.
Means 'become uncouth, boorish, or unfashionable'. Implies a lack of sophistication.
You'll look vulgar/unfashionable if you wear that suit.
When speech, jokes, or content becomes lewd, dirty, or sexually crude.
Specifically means 'become a dirty joke' or 'turn into sexual/vulgar talk'. 下ネタ is a common term for sexual or toilet humor.
His stories quickly become vulgar/dirty.
Means 'become obscene/lewd'. More formal or written than 下ネタになる.
The novel becomes obscene partway through.
Casual/slang for 'become erotic/perverted'. Often used in informal contexts.
The conversation suddenly turned dirty.
When someone's way of speaking becomes rough, using swear words or harsh expressions.
Literally 'language becomes rough'. The most natural way to say someone's speech becomes vulgar or coarse.
When he gets angry, his language becomes vulgar/rough.
Means 'one's mouth becomes bad', i.e., starts speaking harshly or vulgarly.
He gets foul-mouthed when drunk.
下品 (gehin) is a general term for vulgarity, crudeness, or lack of refinement. 卑猥 (hiwai) specifically means obscene or lewd, often used in formal contexts. エロい (eroi) is casual and refers to something sexually suggestive or perverted.
Do not directly translate 'become vulgar' as 俗になる (zoku ni naru) or 下劣になる (geretsu ni naru). These are either unnatural or too strong/archaic. Stick to the options above.