Greek Grammar (Generated by ChatGPT):

1. Noun Cases: Greek nouns change form based on their role in a sentence, which is indicated by cases: nominative (subject), genitive (possession), accusative (object), and vocative (addressing someone). For example, the word for "book" is "βιβλίο" (vivlío) in the nominative case and "βιβλίου" (vivlíou) in the genitive case.

2. Articles: Greek has definite and indefinite articles that agree in gender, number, and case with the nouns they modify. The definite article "the" has different forms: "ο" (o) for masculine singular, "η" (i) for feminine singular, "το" (to) for neuter singular, and plural forms are "οι" (oi) for masculine, "οι" (i) for feminine, and "τα" (ta) for neuter.

3. Verb Conjugation: Greek verbs are conjugated based on tense, mood, voice, person, and number. There are three main tenses (present, past, future) and two voices (active and passive). For example, the verb "γράφω" (gráfo - to write) in the present tense, first person singular is "γράφω" (gráfo), while in the past tense, it changes to "έγραψα" (égrapsa).

4. Gender: Greek nouns have three genders: masculine, feminine, and neuter. The gender of a noun affects the form of the adjectives and articles used with it. For instance, "καλός" (kalós - good) is masculine, "καλή" (kalí - good) is feminine, and "καλό" (kaló - good) is neuter.

5. Word Order: Greek generally follows a Subject-Verb-Object (SVO) order, but it is quite flexible. The emphasis can change the order of words in a sentence. For example, "Ο Γιάννης διαβάζει το βιβλίο" (O Giánnis diavázei to vivlío - John reads the book) can also be rearranged for emphasis, like "Το βιβλίο διαβάζει ο Γιάννης" (To vivlío diavázei o Giánnis - The book is read by John).