Vocatives Identical to the Nominative

40.2 Plural

In the plural, ALL NOUNS/ADJECTIVES simply use their NOMINATIVE PLURAL forms for the VOCATIVE:

• παραδίδοτε, ἄνδρες Ἀθηναῖοι, τὴν πατρίδα.
  • You, Athenian men, are betraying your fatherland.
• παραδίδοτε, ὦ ἄνδρες Ἀθηναῖοι, τὴν πατρίδα.
  • Athenian men, you are betraying your fatherland.

40.3 Neuter

ALL NEUTER nouns/adjectives simply use their NOMINATIVE SINGULAR and PLURAL forms for the VOCATIVE:

• παραδίδως, ὦ τέκνον, τὴν πατρίδα.
  • Child, you are betraying your country.
• παραδίδοτε, ὦ τέκνα, τὴν πατρίδα.
  • Children, you are betraying your country. 

40.4 1st Declension Feminine

ALL 1st DECLENSION FEMININE NOUNS/ADJECTIVES use their NOMINATIVE SINGULAR forms for the VOCATIVE:

• nominative singular: ἡ ἡμέρα, ἡ τέχνη
• vocative singular: ὦ ἡμέρα, ὦ τέχνη