YOU SAID:

I am the grandest of dads

INTO JAPANESE

私は父親の壮大です

BACK INTO ENGLISH

Is my grand father

INTO JAPANESE

私の祖父は、します。

BACK INTO ENGLISH

My grandfather is.

INTO JAPANESE

私の祖父です。

BACK INTO ENGLISH

This is my grandfather.

INTO JAPANESE

これは私の祖父です。

BACK INTO ENGLISH

This is my grandfather.