The vim has a built-in spell check function, which can be turned on and off with a simple command in the terminal.
]s: Move the cursor to the next spelling mistake
[s: Move cursor to previous spelling mistake
After entering set spell, how do I set the spelling error to yellow?
:hi SpellBad ctermbg=yellow
You can also set underline, the foreground color can be anything, if the setting is wrong, you can use
:hi clear SpellBad
Clear off and start over