Which excerpt from a student essay is more formal?
The Ancient Greek civilization existed more than two thousand years ago, but its mythology continues to influence the world today. Ancient Greece was a really long time ago, but Greek myths are totally still around today.
Informal writing is typically used in casual situations or when communicating with someone you know well. Informal language often expresses familiarity and tends to sound more like speech. It uses more conversational language, such as slang, idioms, abbreviations, imprecise language, and contractions.
Formal writing is typically used in academic and business writing or when writing directly to an authority figure. It tends to be more courteous and impersonal, avoiding overly familiar or conversational language.
Compare the following sentences.
Informal: Yeah, ostriches can't fly, but I think they're awesome.
More formal: Ostriches may be flightless, but they're remarkable runners.
Most formal: Though flightless, ostriches are remarkable runners.
The first excerpt from a student essay is more formal. It uses more elevated language (continues to influence the world). The other excerpt uses imprecise language (a really long time ago) and conversational language (totally).