He noticed the bad grammar used by his shipmates, and made a point of mentally correcting and reconstructing their crudities of speech.

To his great joy he discovered that his ear was becoming sensitive and that he was developing grammatical nerves.

A double negative jarred him like a discord, and often, from lack of practice, it was from his own lips that the jar came.

His tongue refused to learn new tricks in a day.
After he had been through the grammar repeatedly, he took up the dictionary and added twenty words a day to his vocabulary.

He found that this was no light task, and at wheel or lookout he steadily went over and over his lengthening list of pronunciations and definitions, while he invariably memorized himself to sleep.