YOU SAID:

I know the longest word in English it's : PNEUMONIAULTRAMICROSCOPICSILIVICONISIS

INTO JAPANESE

私は英語で一番長い単語を知っています: PNEUMONIAULTRAMICROSCOPICSILIVICONISIS

BACK INTO ENGLISH

I know the longest word in English: PNEUMONIAULTRAMICROSCOPICSILIVICONISIS

INTO JAPANESE

私は英語で最も長い単語を知っています: PNEUMONIAULTRAMICROSCOPICSILIVICONISIS

BACK INTO ENGLISH

I know the longest word in English: PNEUMONIAULTRAMICROSCOPICSILIVICONISIS