Tests needed:

nchar in Latin1.
tolower/chartr in Latin1.

x <- "Le français, c'est façile: Règles, Liberté, Egalité, Fraternité..."
a <- "é"; b  <-"è"
save(x,a,b,file="x.rda")

load('x.rda')
c(nchar(x), nchar(x, "b"), nchar(x, "w"))
L1 <- iconv(x, "UTF-8", "Latin1"); Encoding(L1) <- "latin1"
c(nchar(L1), nchar(L1, "b"), nchar(L1, "w"))
toupper(x)
toupper(L1)
chartr(a, b, x)
chartr(a, b, L1)
gsub(a, b, x)
gsub(a, b, L1)
aa <- iconv(a, "UTF-8", "Latin1"); Encoding(aa) <- "latin1"
bb <- iconv(b, "UTF-8", "Latin1"); Encoding(bb) <- "latin1"
chartr(aa, bb, x)
chartr(aa, bb, L1)
gsub(aa, bb, x)
gsub(aa, bb, L1)


In a Latin locale
chartr("\u2019", "'", "abc\u2019")