jomifl, This is getting good, Lets see, 'Seethe' in todays language, and English, as yopu correctly point out, does mean the things you have said, remember, we are talking about things that were written how many Thousands of years ago?, in a now dead language..
Howsomever, It was the Rabbi's, it got to a point where the religion was being changed, and too many meanings put to what was said/written, they got together, and decided what God meant when he'd said something, then codified it so it then couldn't be changed. In writing.
But find someone who practices the Jewish religion, and ask them what 'seethe' means regarding 'thou shalt not seethe the Kid in it mothers milk' I think you'll be surprised at the answer.
Thats why the written word has more significance than the spoken