Who in G-d's Name is "Tamechlom"?

Recently, I had the opportunity to hear someone make hamotzi for some other people (but not for me). To my surprise, the berachah was directed to a deity that I didn't recognize.

"Baruch Tamechlom hamotzi lechem min ha'aretz."

That's a verbatim transliteration of what was said. My transliteration didn't skip any syllables, although I may have subconsciously added one or two.

I've heard some other people praying to this deity, and I just don't understand it. Every other word in the berachah is enunciated properly. So why are the most important words so badly mangled? Is that particular combination of letters a tongue-twister?

I remember that in yeshivah, guys would take turns making havdalah for everyone, until this problem became so bad that the job had to be done by one person who could actually say the words properly. Surely mechanchim could teach their students how to speak Hebrew, especially the most important words of all.