diff --git a/card-functionality/src/tests.rs b/card-functionality/src/tests.rs
index 4a9613e..004625d 100644
--- a/card-functionality/src/tests.rs
+++ b/card-functionality/src/tests.rs
@@ -334,7 +334,7 @@ pub fn test_set_user_data(
     card_client.set_name(b"Bar<<Foo")?;
 
     // lang
-    card_client.set_lang(b"deen")?;
+    card_client.set_lang(&[['d', 'e'].into(), ['e', 'n'].into()])?;
 
     // sex
     card_client.set_sex(Sex::Female)?;
@@ -348,7 +348,7 @@ pub fn test_set_user_data(
     assert_eq!(ch.name().as_deref(), Some("Bar<<Foo".as_bytes()));
     assert_eq!(
         ch.lang().expect("Language setting is None"),
-        &[[b'd', b'e'], [b'e', b'n']]
+        &[['d', 'e'].into(), ['e', 'n'].into()]
     );
     assert_eq!(ch.sex(), Some(Sex::Female));
 
diff --git a/openpgp-card-sequoia/src/card.rs b/openpgp-card-sequoia/src/card.rs
index 9d622a6..8eddd33 100644
--- a/openpgp-card-sequoia/src/card.rs
+++ b/openpgp-card-sequoia/src/card.rs
@@ -14,7 +14,7 @@ use openpgp_card::algorithm::{Algo, AlgoInfo, AlgoSimple};
 use openpgp_card::card_do::{
     ApplicationIdentifier, ApplicationRelatedData, CardholderRelatedData,
     ExtendedCapabilities, ExtendedLengthInfo, Fingerprint, HistoricalBytes,
-    KeyGenerationTime, PWStatusBytes, SecuritySupportTemplate, Sex,
+    KeyGenerationTime, Lang, PWStatusBytes, SecuritySupportTemplate, Sex,
 };
 use openpgp_card::{CardClient, Error, KeySet, KeyType, Response};
 
@@ -411,12 +411,12 @@ impl Admin<'_, '_> {
         self.oc.card_client.set_name(name.as_bytes())
     }
 
-    pub fn set_lang(&mut self, lang: &str) -> Result<Response, Error> {
+    pub fn set_lang(&mut self, lang: &[Lang]) -> Result<Response, Error> {
         if lang.len() > 8 {
             return Err(anyhow!("lang too long").into());
         }
 
-        self.oc.card_client.set_lang(lang.as_bytes())
+        self.oc.card_client.set_lang(lang)
     }
 
     pub fn set_sex(&mut self, sex: Sex) -> Result<Response, Error> {
diff --git a/openpgp-card-sequoia/src/main.rs b/openpgp-card-sequoia/src/main.rs
index 558c133..f3e0bc1 100644
--- a/openpgp-card-sequoia/src/main.rs
+++ b/openpgp-card-sequoia/src/main.rs
@@ -111,7 +111,7 @@ fn main() -> Result<(), Box<dyn Error>> {
         let res = admin.set_sex(Sex::NotApplicable)?;
         println!("set sex {:x?}", res);
 
-        let res = admin.set_lang("en")?;
+        let res = admin.set_lang(&[['e', 'n'].into()])?;
         println!("set lang {:x?}", res);
 
         let res = admin.set_url("https://keys.openpgp.org")?;
diff --git a/openpgp-card/src/card_do.rs b/openpgp-card/src/card_do.rs
index 9e1aeef..65a3f87 100644
--- a/openpgp-card/src/card_do.rs
+++ b/openpgp-card/src/card_do.rs
@@ -285,7 +285,7 @@ pub struct ExtendedLengthInfo {
 #[derive(Debug, PartialEq)]
 pub struct CardholderRelatedData {
     name: Option<Vec<u8>>,
-    lang: Option<Vec<[u8; 2]>>,
+    lang: Option<Vec<Lang>>,
     sex: Option<Sex>,
 }
 
@@ -298,6 +298,45 @@ pub enum Sex {
     NotApplicable,
 }
 
+#[derive(Debug, PartialEq, Clone, Copy)]
+pub enum Lang {
+    Value([u8; 2]),
+    Invalid(u8),
+}
+
+impl From<(char, char)> for Lang {
+    fn from(c: (char, char)) -> Self {
+        Lang::Value([c.0 as u8, c.1 as u8])
+    }
+}
+
+impl From<[char; 2]> for Lang {
+    fn from(c: [char; 2]) -> Self {
+        Lang::Value([c[0] as u8, c[1] as u8])
+    }
+}
+
+impl From<Lang> for Vec<u8> {
+    fn from(lang: Lang) -> Self {
+        match lang {
+            Lang::Value(v) => vec![v[0], v[1]],
+            Lang::Invalid(v) => vec![v],
+        }
+    }
+}
+
+impl From<&[u8; 1]> for Lang {
+    fn from(data: &[u8; 1]) -> Self {
+        Lang::Invalid(data[0])
+    }
+}
+
+impl From<&[u8; 2]> for Lang {
+    fn from(data: &[u8; 2]) -> Self {
+        Lang::Value([data[0], data[1]])
+    }
+}
+
 impl From<&Sex> for u8 {
     fn from(sex: &Sex) -> u8 {
         match sex {
diff --git a/openpgp-card/src/card_do/cardholder.rs b/openpgp-card/src/card_do/cardholder.rs
index cd6834d..434526f 100644
--- a/openpgp-card/src/card_do/cardholder.rs
+++ b/openpgp-card/src/card_do/cardholder.rs
@@ -7,7 +7,7 @@ use std::convert::TryFrom;
 
 use anyhow::Result;
 
-use crate::card_do::{CardholderRelatedData, Sex};
+use crate::card_do::{CardholderRelatedData, Lang, Sex};
 use crate::tlv::{value::Value, Tlv};
 
 impl CardholderRelatedData {
@@ -15,7 +15,7 @@ impl CardholderRelatedData {
         self.name.as_deref()
     }
 
-    pub fn lang(&self) -> Option<&[[u8; 2]]> {
+    pub fn lang(&self) -> Option<&[Lang]> {
         self.lang.as_deref()
     }
 
@@ -34,9 +34,17 @@ impl TryFrom<&[u8]> for CardholderRelatedData {
         let name: Option<Vec<u8>> =
             tlv.find(&[0x5b].into()).map(|v| v.serialize().to_vec());
 
-        let lang: Option<Vec<[u8; 2]>> = tlv
-            .find(&[0x5f, 0x2d].into())
-            .map(|v| v.serialize().chunks(2).map(|c| [c[0], c[1]]).collect());
+        let lang: Option<Vec<Lang>> =
+            tlv.find(&[0x5f, 0x2d].into()).map(|v| {
+                v.serialize()
+                    .chunks(2)
+                    .map(|c| match c.len() {
+                        2 => Lang::from(&[c[0], c[1]]),
+                        1 => Lang::from(&[c[0]]),
+                        _ => unreachable!(),
+                    })
+                    .collect()
+            });
 
         let sex = tlv
             .find(&[0x5f, 0x35].into())
@@ -66,7 +74,7 @@ mod test {
             ch,
             CardholderRelatedData {
                 name: Some("Bar<<Foo".as_bytes().to_vec()),
-                lang: Some(vec![[b'd', b'e'], [b'e', b'n']]),
+                lang: Some(vec![['d', 'e'].into(), ['e', 'n'].into()]),
                 sex: Some(Sex::Female)
             }
         );
diff --git a/openpgp-card/src/lib.rs b/openpgp-card/src/lib.rs
index cfbf14b..c85371e 100644
--- a/openpgp-card/src/lib.rs
+++ b/openpgp-card/src/lib.rs
@@ -48,7 +48,7 @@ use crate::apdu::commands;
 use crate::apdu::response::RawResponse;
 use crate::card_do::{
     ApplicationRelatedData, CardholderRelatedData, Fingerprint,
-    KeyGenerationTime, PWStatusBytes, SecuritySupportTemplate, Sex,
+    KeyGenerationTime, Lang, PWStatusBytes, SecuritySupportTemplate, Sex,
 };
 use crate::crypto_data::{
     CardUploadableKey, Cryptogram, Hash, PublicKeyMaterial,
@@ -755,8 +755,14 @@ impl<'a> dyn CardClient + 'a {
         apdu::send_command(self, put_name, false)?.try_into()
     }
 
-    pub fn set_lang(&mut self, lang: &[u8]) -> Result<Response, Error> {
-        let put_lang = commands::put_lang(lang.to_vec());
+    pub fn set_lang(&mut self, lang: &[Lang]) -> Result<Response, Error> {
+        let bytes: Vec<u8> = lang
+            .iter()
+            .map(|&l| Into::<Vec<u8>>::into(l))
+            .flatten()
+            .collect();
+
+        let put_lang = commands::put_lang(bytes);
         apdu::send_command(self, put_lang, false)?.try_into()
     }
 
diff --git a/tools/src/bin/opgpcard/main.rs b/tools/src/bin/opgpcard/main.rs
index 08f2f4b..935cdca 100644
--- a/tools/src/bin/opgpcard/main.rs
+++ b/tools/src/bin/opgpcard/main.rs
@@ -215,14 +215,7 @@ fn print_status(ident: Option<String>, verbose: bool) -> Result<()> {
     }
 
     if let Some(lang) = crd.lang() {
-        let lang = lang
-            .iter()
-            .map(|lang| {
-                lang.iter().map(|&u| char::from(u)).collect::<String>()
-            })
-            .collect::<Vec<_>>()
-            .join(", ");
-        println!("Language preferences '{}'", lang);
+        println!("Language preferences '{:?}'", lang);
     }
 
     // information about subkeys