The longest English word would take three and a half hours to say out loud.
The full, technical name of the protein commonly known as "titin" (which helps keep our muscles elastic) is 189,819 letters long. The reason is that this protein consists of 34,350 amino acids.
If you want to see this long word, here is a site that has it.
https://www.digitalspy.com/fun/a4447...-to-pronounce/