Somerset Maugham was a good and careful grammarian but now and then he slipped. In The Letter, a solicitor, Mr. Joyce, is approached by a Mr. Crosbie: He spoke beautiful English, accenting each word with precision, and Mr. Joyce had often wondered at the extent of his vocabulary....
Somerset Maugham was a grammarian who sometimes slipped.  In the letter, solicitor, Mr. Joyce, is approached by Mr. Crosbie, speaking English and Mr. Joyce often wondered at the extant of his vocabulary