I have a thick accent and find some words like "hippopotamus" difficult to pronounce.
What accent or dialect do you use?
My mother tongue is German. Hippopotamus is Nilferd. Sounds funny to you, yes? Like a bad name for nert?
Nilferd?  That's interesting.  What other words are tough to pronounce ?
Ah, let me think...
I read that English allows for different pronunciations and even spellings of the same word.
Very true. It is difficult. Words like "regularly" and "brewery" and "hereditary". Kind of a pattern, I think
Yes, seems like a vowel or a y after an r seems to be more difficult to pronounce.
A funny challenge from a teacher: try to say "red lorry, yellow lorry" many times fast. VERY hard for me!
Red Lorry Yellow Lorry
Red Lorry Yellow Lorry, also known very briefly as the Lorries, are a post-punk band that were formed in Leeds, England in early 1981.
History.
The band was formed by guitarist/songwriter Chris Reed and vocalist Mark Sweeney, along with bassist Steve Smith and drummer Mick Brown (who would later join The Mission). Sweeney left the band in late 1981 and Reed permanently took over as vocalist, with Martin Fagan joining as a second guitarist. The group's sound
quoted a Stanford grad student describing something called the "California vowel shift": "If you try to think about what you think a surfer or a skater or a valley girl talks like, and do it, you can feel your mouth feels different. And I think that has to do a lot with the way that the vowels are shifting." At a SXSW Q&A panel, Armisen said that to do the "Californians" accent: "You have to pronounce every single consonant and vowel." According to Hader