diff --git a/profile.d/lang.sh b/profile.d/lang.sh
index 49cc23d..1dab605 100644
--- a/profile.d/lang.sh
+++ b/profile.d/lang.sh
@@ -37,14 +37,48 @@
 load_conf lang
 
 # ------------------------------------------------------------------------------
-# check if a given locale is installed on the system
+# check if a given locale is installed on the system.
+# The comparison is tolerant to the various ways the codeset can be written
+# across distributions (UTF-8, UTF8, utf8, utf-8, ISO-8859-1, iso88591, ...).
+# On success the canonical name, exactly as the system spells it, is printed on
+# stdout so callers can feed it verbatim to `export LANG=...` etc.
+# Usage: canonical=$(locale_check <locale>) || handle-missing
 locale_check()
 {
-    locale -a | grep -qx "$1" || {
-        disp W "Locale '$1' is not installed on this system."
-        return 1
-    }
-    return 0
+    local requested="$1"
+    [[ -z $requested ]] && { disp W "No locale given to check."; return 1; }
+
+    # Split "lang_TERRITORY[.codeset][@modifier]" into base, codeset, modifier.
+    local req_body="$requested" req_cs="" req_mod=""
+    [[ $req_body == *@* ]] && { req_mod="${req_body##*@}"; req_body="${req_body%@*}"; }
+    [[ $req_body == *.* ]] && { req_cs="${req_body##*.}";  req_body="${req_body%.*}"; }
+
+    # Normalise the codeset: lowercase then strip every non-alphanumeric char so
+    # that UTF-8, UTF8, utf8 and utf-8 all compare equal (likewise ISO variants).
+    local req_cs_norm="${req_cs,,}"
+    req_cs_norm="${req_cs_norm//[^a-z0-9]/}"
+
+    local cand body cs mod cs_norm
+    while IFS= read -r cand; do
+        [[ -z $cand ]] && continue
+        body="$cand"; cs=""; mod=""
+        [[ $body == *@* ]] && { mod="${body##*@}"; body="${body%@*}"; }
+        [[ $body == *.* ]] && { cs="${body##*.}";  body="${body%.*}"; }
+        cs_norm="${cs,,}"
+        cs_norm="${cs_norm//[^a-z0-9]/}"
+
+        # Base language and modifier must match exactly.
+        [[ $body == "$req_body" && $mod == "$req_mod" ]] || continue
+        # A requested codeset must match (normalised); if none was requested,
+        # accept any codeset the system provides.
+        [[ -z $req_cs_norm || $cs_norm == "$req_cs_norm" ]] || continue
+
+        printf '%s\n' "$cand"
+        return 0
+    done < <(locale -a 2>/dev/null)
+
+    disp W "Locale '$requested' is not installed on this system."
+    return 1
 }
 export -f locale_check
 
@@ -85,7 +119,9 @@ setlocale()
     local loc=$1
     [[ -z $loc ]] && disp E "No locale specified." && return 1
 
-    locale_check "$loc" || return 1
+    # Resolve to the exact spelling installed on this system, tolerant to the
+    # various codeset writings (UTF-8, UTF8, utf8, utf-8, ...).
+    loc=$(locale_check "$loc") || return 1
 
     export LANG=$loc
     export LC_MESSAGES=$loc
@@ -108,6 +144,7 @@ setc()
 {
     # Locale definitions
     export LC_ALL=C
+    export LANG=C
     disp I "Locale changed to standard C (POSIX)."
 }
 export -f setc