It’s like they speak in vowels only, it’s so soft.
Well there’s a huge variety of different accents in England, even more if you include the whole UK. British people themselves can struggle understanding other Brits from just 100 or 200 miles down the road. I say that as a Brit - I’ve worked in call centres where there would frequently be Liverpudlians, Geordies, Cornish etc calling back in a rage after being hung up on multiple times by colleagues who couldn’t understand them.
After my German father sheepishly admitted to some fellow British pilots that he couldn’t understand Welsh radio messages he was relieved to hear that the Brits couldn’t understand the Welsh either.
There’s a wide variety of English accents, so it might help if you specified which one.
What accent?
The language is actually from there so we (everyone else) are the ones with accent.