A look at the Greek language from the POV of how hard it is for an English speaker to learn it. The truth is that Greek is a very hard language to learn, and Ancient Greek is probably one of the most Godawful languages on Earth to learn.
Greek is a difficult language to learn, and it’s rated the second hardest language to learn by language professors. It’s easy to learn to speak simply, but it’s quite hard to get it down like a native. It’s the rare second language learner who attains native competence. Like English, the spelling doesn’t seem to make sense, and you have to memorize many words. Further, there is the unusual alphabet. However, the orthography is quite rational, about as good as that of Spanish. Whether or not Greek is an irregular language is controversial. It has that reputation, but some say it is not as irregular as it seems.
Greek has four cases: nominative, accusative, genitive and vocative (used when addressing someone). There are three genders: masculine, feminine and neuter. Nouns have several different declension patterns determined by the ending on the noun. Verb conjugations are about as complicated as in Romance. Greek does retain the odd aorist tense. Greek syntax is quite complicated.
Greek gets a 5 rating, extremely difficult to learn.
Classic or Ancient Greek is worse, with a distinction between aspirated and unaspirated consonants, a pitch accent system and a truly convoluted, insanely irregular system of noun and verb inflection. It has a dual number in addition singular and plural and it has a very difficult optative case. Irregular verbs have one of six different stem types. The grammar is one of the most complex of all languages and the phonology and morphology are truly convoluted.
Classic Greek gets a 5 rating, hardest of all.