BY MISTAKE

Afrikaans

per abuis (by), abusieflik (by). (various references)

Albanian

gabimisht (by error, crosswise, erroneously, incorrectly, mistakenly, wrongly). (various references)

Arabic 

‏عن طريق الخطأ, ‏بالخطأ. (various references)

Bulgarian 

погрешно (mis-, mistakenly, wrong, wrongly), по погрешка. (various references)

Chinese 

忽略 (forget about; neglect; leave out by mistake). (various references)

Czech

omylem (erroneously, mistakenly), náhodou (accidentally, at random, by chance, if and when, occasionally, perchance). (various references)

Dutch

bý vergissing, verkeerd (erroneous, incorrect, mistaken, wrong), per abuis, abusievelýk. (various references)

Esperanto

erare. (various references)

Finnish

erehdyksestä (as a result of a mistake, inadvertently). (various references)

French

par erreur, abusivement. (various references)

Frisian

by fersin, troch fersin. (various references)

German

aus versehen, irrtümlich (erroneous). (various references)

Hebrew 

בשוגג, בשגגה (by error, unwitting), בטעות (mistakenly). (various references)

Hungarian

tévedésbõl. (various references)

Indonesian

tersilap (done by mistake). (various references)

Italian

inavvertitamente (accidentally, inadvertently, unawares). (various references)

Japanese Kanji 

過って (by accident, in error), 誤って (by accident, in error), ちんどん屋 (against one's better judgement, determinedly, have been -ing, hoodlum, just, keep -ing, penis, quite, to leave, traditional Japanese band of sandwich board advertisers, unconsciously, unintentionally, walking briskly). (various references)

Japanese Katakana 

つい (against one's better judgement, just, quite, unconsciously, unintentionally), あやまって (by accident, in error). (various references)

Pig Latin

ybay istakemay.(various references)

Romanian

din greşealã (unwillingly). (various references)

Russian 

по ошибке (erroneously). (various references)

Serbo-Croatian

greškom (mistake: by mistake). (various references)

Spanish

por error, por equivocación. (various references)

Swedish

av misstag (mistakenly). (various references)

Turkish

yanlışlıkla (by an oversight, erroneously, inadvertently, incorrectly, mistakenly, through an oversight). (various references)

Ukrainian

помилково (crosswise, mistakenly, wrong, wrongly). (various references)