Wrong.
There is no way you can accurately write Thai words using Roman letters and hope to get the sound right. There are several transliteration schemes currently in use for Thai to English transliteration. I've used the one Thai2English.com uses:
"yoot" is pronounced without any "h" sound in front. The "h" is there to modify the tone to low.
There is no word in Thai such as ยุด (i.e. "yoot" without the "H" in front - หยุด without the ห in front), so I can't illustrate what "yoot" would sound like without the "H".
However, you can compare "divorced" and "grandma".
The haw heep is there in หย่า (divorced) "yàa" to make it low tone. Otherwise it would be ย่า (grandmother) "yâa" - falling tone.