Difference in Pronouncing Chieut and Jieut

For the consonant lesson about chieut and jieut, both consonants seem like they are pronounced “ch”.  Am I correct?  If so, that means the only difference between the consonants is the romanization spelling and the Hangul writing. 

Good question! This can be a little tricky as the Korean romanization isn't always an accurate reflection of the pronunciation of the hangul. 

ㅈ (Jieut) and ㅊ (chieut) can both be pronounced as a "ch" sound, depending on where they appear in a word. 
 

ㅈ (Jieut) 
 

ㅈ (Jieut) can be pronounced as either a “ch, “j,” or "t" sound, depending on where it appears. As a general rule:

* At the start of a word it’s pronounced like a softer version of the English “ch” sound.
* In the middle of a word, or when followed by a vowel with a “y” or “i” sound, it’s pronounced like a softer version of the English “j” sound.

* At the ends of words or syllables, it's pronounced with an unaspirated “t” sound, like the “t” in “hot.” 
 

At the start of words or in the middle of words, the ㅈ (jieut) consonant is romanized as "j"; at the end of words or syllables, it's romanized as "t."

ㅊ (Chieut) 

ㅈ (Jieut) can be pronounced as either a “ch” or a “t” sound, depending on where it appears. As a general rule:

* At the start of a word or syllable, or when followed by a vowel with a “y” or “i” sound, it’s pronounced as a hard “ch” sound, like the “ch” in “cheese.” Here, it’s an aspirated sound, meaning you should push lots of air out of your mouth when you say it.
* At the end of a word or syllable, it’s pronounced with an unaspirated sound, like the “t” in “hot.”
 

At the start of words or in the middle of words, the ㅊ (chieut) consonant is romanized as "ch"; at the end of words or syllables, it's romanized as "t."
 

To summarize, although ㅈ (jieut) and ㅊ (chieut) can both be pronounced as "ch," ㅊ (chieut) is an aspirated "ch" sound, meaning it's pronounced with a much stronger sound than ㅈ (jieut) and should be pronounced by pushing lots of air out of your mouth when you say it. 
 

I hope this helps!