"꽃", "것", "곧", "곳" (There are three distinct sounds, as 곧 and 곳 pronounces the same when they are by themselves) 1. Starting consonant ㄲ and ㄱ (and ㅋ) If you pronounce the beginning consonant of "cuando" (Spanish) very forcefully, you get a sound similar to ㄲ. If you make it guttural (lighten the front part of the mouth and tense your throat area), it gets closer to ㄱ. There is another related sound, ㅋ, which is similar to English [k] (aspirated). 2. The vowel ㅗ and ㅓ. 오 is like the first part of English "oh", while 어 resembles the vowel sound in "gut" or "pun". Most Korean vowels have no transitioning in it. They are flat with the same sound maintained throughout. 3. Ending consonant ㅊ, ㅅ, and ㄷ. These ending consonants are both unvoiced and unreleased (ㅁ and ㅇ are exceptions to this). There is neither a vibration of the vocal cord nor detectable sound made at the end with the final release. For example, "Bob" in English will have the light [b] sound at the end that you can hear. 밥 on the other hand has no such sound. The release of the ending sound is too light and unclear to be distinguished. Because of this, syllables ending in ㄷ, ㅅ/ㅆ, ㅈ, ㅊ, and ㅌ all sound the same when they are not followed by a vowel. (And I don't mean just hard to distinguish. They are exactly the same no matter how accurately spoken) They only become different when a vowel makes them voiced, as in 자, 사, 걷어 [거더], 꽃이다 [꼬치다], etc. Likewise, ㄱ/ㄲ, ㅋ, and ㅂ,ㅍ are indistinguishable among themselves. But the three different groups (ㄱ, ㄷ, and ㅂ) are distinguishable from one another. You should learn by hearing and practicing the real sounds - here's one YouTube site that can help you. https://www.youtube.com/watch?v=0ZhOeA0RD9o