Example image of eyePlorer eyePlorer map for 'Three letter rule': English orthography Function word Letter (alphabet) Lexical item Homograph Phoneme Otto Jespersen Stress (linguistics) Syllable Weak form and strong form Interjection Inflection Old English Punctuation John Milton Meter (poetry) Paradise Lost Conversion (linguistics) Lexical category Auxiliary verb Lexical verb Loanword Romanization Greek alphabet Italian language Latin Qi Solfège Exception that proves the rule Abbreviation Nickname Silent letter