이다 verb *입니다(formal speech at workplace to your boss/on media or printed materials/public speech/strangers despite the ages) *야 (plain speech to your close friends at the similar age or to the younger ones) *이야 *consonant ending NOUN + 이에요 (most common informal polite speech most people use among colleagues or older family members) *vowel ending NOUN + 예요 (most common informal polite speech most people use among colleagues or older family members)