diff --git a/DESCRIPTION b/DESCRIPTION
index 02fb8e59..e1a3e565 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -48,7 +48,8 @@ Imports:
     rlang,
     testthat,
     utils,
-    xml2
+    xml2,
+    withr
 Suggests:
     baseline,
     bookdown,
diff --git a/R/DEPRECATED-read.mat.Witec.R b/R/DEPRECATED-read.mat.Witec.R
index 7eec132e..af1d2700 100644
--- a/R/DEPRECATED-read.mat.Witec.R
+++ b/R/DEPRECATED-read.mat.Witec.R
@@ -57,7 +57,10 @@ hySpc.testthat::test(read.mat.Witec) <- function() {
   test_that(
     "deprecated",
     expect_warning(
-      expect_error(read.mat.Witec(file = ""), "Can only read a MAT file"),
+      expect_error(
+        with_envvar(list(LANGUAGE = "en_US"), read.mat.Witec(file = "")),
+        "Can only read a MAT file"
+      ),
       "deprecated|supports"
     )
   )
diff --git a/R/DEPRECATED-read.spc.R b/R/DEPRECATED-read.spc.R
index 2600832a..9ed908ed 100644
--- a/R/DEPRECATED-read.spc.R
+++ b/R/DEPRECATED-read.spc.R
@@ -855,7 +855,10 @@ hySpc.testthat::test(read.spc) <- function() {
   test_that(
     "deprecated",
     expect_warning(
-      expect_error(read.spc(file = ""), "can only read"),
+      expect_error(
+        with_envvar(list(LANGUAGE = "en_US"), read.spc(file = "")),
+        "can only read"
+      ),
       "deprecated"
     )
   )
diff --git a/R/DEPRECATED-read.spe.R b/R/DEPRECATED-read.spe.R
index 20ca1d0f..e69286ed 100644
--- a/R/DEPRECATED-read.spe.R
+++ b/R/DEPRECATED-read.spe.R
@@ -361,7 +361,10 @@ hySpc.testthat::test(read.spe) <- function() {
   test_that(
     "deprecated",
     expect_warning(
-      expect_error(read.spe(filename = ""), "can only read"),
+      expect_error(
+        with_envvar(list(LANGUAGE = "en_US"), read.spe(filename = "")),
+        "can only read"
+      ),
       "deprecated"
     )
   )
diff --git a/R/DEPRECATED-read.txt.Renishaw.R b/R/DEPRECATED-read.txt.Renishaw.R
index 3746e004..e283e540 100644
--- a/R/DEPRECATED-read.txt.Renishaw.R
+++ b/R/DEPRECATED-read.txt.Renishaw.R
@@ -172,7 +172,10 @@ hySpc.testthat::test(read.txt.Renishaw) <- function() {
   test_that(
     "deprecated",
     expect_warning(
-      expect_error(read.txt.Renishaw(file = ""), "cannot open"),
+      expect_error(
+        with_envvar(list(LANGUAGE = "en_US"), read.txt.Renishaw(file = "")),
+        "cannot open"
+      ),
       "deprecated"
     )
   )
@@ -199,7 +202,13 @@ hySpc.testthat::test(read.zip.Renishaw) <- function() {
   test_that(
     "deprecated",
     expect_warning(
-      expect_error(read.zip.Renishaw(file = ""), "cannot open"),
+      expect_error(
+        with_envvar(
+          list(LANGUAGE = "en_US"),
+          read.zip.Renishaw(file = "")
+        ),
+        "cannot open"
+      ),
       "deprecated"
     )
   )
diff --git a/R/DEPRECATED-read.txt.Shimadzu.R b/R/DEPRECATED-read.txt.Shimadzu.R
index 7559f405..a611dd6c 100644
--- a/R/DEPRECATED-read.txt.Shimadzu.R
+++ b/R/DEPRECATED-read.txt.Shimadzu.R
@@ -232,7 +232,10 @@ hySpc.testthat::test(read.txt.Shimadzu) <- function() {
   test_that(
     "deprecated",
     expect_warning(
-      expect_error(read.txt.Shimadzu(file = ""), "attempt to select"),
+      expect_error(
+        with_envvar(list(LANGUAGE = "en_US"), read.txt.Shimadzu(file = "")),
+        "attempt to select"
+      ),
       "deprecated"
     )
   )
diff --git a/R/plot.R b/R/plot.R
index 6bc2134a..e036e2a4 100644
--- a/R/plot.R
+++ b/R/plot.R
@@ -156,6 +156,7 @@ setGeneric("plot")
 #' @concept plot generation
 #'
 #' @export
+#' @importFrom withr with_envvar
 #' @examples
 #'
 #' plot(flu)
@@ -199,7 +200,10 @@ hySpc.testthat::test(.plot) <- function() {
     expect_warning(plot(hy_spectra, "c"), "Intensity at first wavelengh only is used.")
 
     # Regular tests: errors ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-    expect_error(plot(hy_spectra, "depth"), "object 'z' not found")
+    expect_error(
+      with_envvar(list(LANGUAGE = "en_US"), plot(hy_spectra, "depth")),
+      "object 'z' not found"
+    )
     expect_error(plot(hy_spectra[0, ]), "No spectra.")
     expect_error(plot(hy_spectra, xoffset = "a"), "xoffset must be a numeric")
     expect_error(plot(hy_spectra, func = "a"), "func needs to be a function")