Not sure if it’s what you mean, but you can do this:
plot(1:10, xaxt = "n", xlab='Some Letters')
axis(1, at=1:10, labels=letters[1:10])
which then gives you the graph:
Not sure if it’s what you mean, but you can do this:
plot(1:10, xaxt = "n", xlab='Some Letters')
axis(1, at=1:10, labels=letters[1:10])
which then gives you the graph: