I used to think the "th" sound is hard because it is uncommon in my language, we do not use our tongues to hit the top teeth like that. But then, it became 2nd nature after living abroad for almost 20 years.

Recently i happen to work with a lot of architects and designers and 1 word comes up which I think is the most difficult to pronouncr: AESTHETIC.

It sounds very simple but if you break down the syllables, your tongue needs to do a bit of work.

For the British English version, the "t" in tic is pronounced quite strong, as in "tick". Mostly, your tongue only needs to worry about the "THE" sound, i.e. ES-THE-TIC.

In US English, the "t" is most often pronounced as a soft "d". This means "TIC" will sound like "DIC". So your tongue needs to flick up for the "THE" sound and then immediately flick down for the "DIC".

This gets even harder if you consider the adverb: AESTHETICALLY. A lot of tongue gymnasium involve...

Any other words or phrase that you think is dificult?