A computer-implemented method includes recognizing, by a computer device, a word as a new learned word for a user; registering, by the computer device, the new leaned word in a user's new learned word list as a registered new learned word; associating, by the computer device, the registered new learned word with related known words in a user's known word library, the known word library including words known to the user; tracking, by the computer device, uses of the related known words by the user; identifying, by the computer device, a used sentence used by the user that contains one of the related known words; and suggesting, by the computer device, to the user a new sentence that replaces the one of the related known words in the used sentence with the new learned word.