좋은 아침이에요.(jo-eun-achimee-eh-yo) is a polite way to say good morning. It is used to someone who is older than you or someone you have to treat politely.
좋은 아침(jo-eun-achim) is a casual form of good morning. You use it to someone who is the same age as you or younger than you.
안녕히 주무셨어요?(annyong-hee-jumu-sheosseo-yo) is a polite form of "Did you sleep well?"
잘 잤어?(jal-jasseo) is a casual form of "Did you sleep well?"
안녕히 주무세요.(annyong-hee-jumu-se-yo) is a polite form of good night.
잘 자(jal-ja) is a casual form of good night.
Korean uses 고맙습니다 or 감사합니다 to thank someone. Even the words are different, they share the same meaning. The only difference between them is 고맙습니다 is a native Korean word and 감사합니다 is a Sino-Korean word.
고맙습니다 or 감사합니다(ko-mahp-seumnee-da or kamsa-hamnee-da) is a polite term of thank you.
고마워요 or 감사해요(komahwo-yo or kamsa-hae-yo) is a semi-casual form to say thank you.
고마워(komawo) is a casual form to say thank you.
진심으로 고맙습니다 or 진심으로 감사합니다(jin-simeu-ro-komap-seumneeda or kamsa-hapnee-da) is a polite way of saying "Thank you very much".
진심으로 고마워(jin-simeu-ro-komawo) is a casual term to say "Thank you very much".
정말 고맙습니다 or 정말 감사합니다(chongmal-ko-map-seumnee-da or chongmal-kamsa-hamnee-da) is a polite way to say "Many Thanks".
정말 고마워(chongmal-komahwo) is a casual way to say "Many Thanks".
실례합니다 or 실례하겠습니다(silleh-hamnee-da or silleh-haget-seumnee-da) is a polite term to say "Excuse me".
실례해요(silleh-hae-yo) is a semi-casual form to say "Excuse me".
실례지만 or 실례합니다만(silleh-jee-man or silleh-hamnee-da-man) is a polite way to say "Excuse me, but.."
실례 좀 해도 되겠습니까?(silleh-jom-hae-do-dae-get-seumnee-kka) is a polite way of saying "Excuse me, can I bother you for a moment?".
죄송하지만 or 죄송합니다만(je-song-ha-jee-man or je-song-hamnee-da-man) is a polite term to say "I'm sorry, but..".
미안하지만..(mi-an-ha-jee-man) is a semi-casual way to say "I'm sorry, but..".