I cannot access your data link because the permission is not set correctly. I invented a little data set as an alternative. The key to setting the colors is changing the order of the factor levels of manner. The default is to set the levels alphabetically. In the code below, I show the default and the effect of setting the levels manually.
library(tidyverse)
#> Warning: package 'tibble' was built under R version 4.1.2
sm <- data.frame(f_word_ = rep(1:10, 2),
est = c(1:10 *2, 1:10*2 + 5),
lower_ci = c(1:10 * 2 -1, 1:10 * 2 +4),
upper_ci = c(1:10 * 2 +1, 1:10 * 2 +6),
manner = rep(c("fricative", "nasal"), each = 10))
ggplot(sm, aes(f_word_, est)) +
geom_ribbon(aes(ymin = lower_ci, ymax = upper_ci, fill=manner), alpha = 0.3) +
geom_line(aes(colour = manner))