diff --git a/docs/dsp-tools-create-ontologies.md b/docs/dsp-tools-create-ontologies.md
index e8904f419..89339ee69 100644
--- a/docs/dsp-tools-create-ontologies.md
+++ b/docs/dsp-tools-create-ontologies.md
@@ -141,8 +141,8 @@ By convention, property names start with a lower case letter.
 
 `"labels": {"<language>": "<string>", ...}`
 
-Collection of `labels` for the property as strings with language tag (currently "en", "de", "fr"
-and "it" are supported).
+Collection of `labels` for the property as strings with language tag (currently "en", "de", "fr", "it",
+and "rm" are supported).
 
 ### Comments
 
@@ -150,7 +150,7 @@ and "it" are supported).
 
 `"comments": { "<lang>": "<comment>", "<lang>": "<comment>", ... }`
 
-Comments with language tags. Currently, "de", "en", "fr" and "it" are supported. The `comments` element is optional.
+Comments with language tags. Currently, "de", "en", "fr", "it", and "rm" are supported. The `comments` element is optional.
 
 ### Super
 
@@ -780,8 +780,8 @@ By convention, resource names start with a upper case letter.
 
 `"labels": {"<language>": "<string>", ...}`
 
-Collection of `labels` for the resource as strings with language tag (currently "en", "de", "fr"
-and "it" are supported).
+Collection of `labels` for the resource as strings with language tag (currently "en", "de", "fr", "it", 
+and "rm" are supported).
 
 ### Super
 
@@ -844,7 +844,7 @@ resource can have as well as how many times the relation is established.
 
 `"comments": { "<lang>": "<comment>", "<lang>": "<comment>", ... }`
 
-Comments with language tags. Currently, "de", "en", "fr" and "it" are supported. The `comments` element is optional.
+Comments with language tags. Currently, "de", "en", "fr", "it", and "rm" are supported. The `comments` element is optional.
 
 Example for a resource definition:
 
diff --git a/docs/dsp-tools-create.md b/docs/dsp-tools-create.md
index def88d819..97c72ae40 100644
--- a/docs/dsp-tools-create.md
+++ b/docs/dsp-tools-create.md
@@ -167,7 +167,7 @@ The longname is a string that provides the full name of the project.
 
 `"descriptions": {"<lang>": "<string>", ...}`
 
-The description is represented as a collection of strings with language tags (currently "en", "de", "fr" and "it" are
+The description is represented as a collection of strings with language tags (currently "en", "de", "fr", "it", and "rm" are
 supported). It is the description of the project.
 
 ### Keywords
@@ -201,9 +201,9 @@ A node of a list may have the following elements:
 
 - _name_: Name of the node as string. It is mandatory and has to be unique within the list.
 - _labels_: Label with language tags in the form `{ "<lang>": "<label>", "<lang>": "<label>", ... }`. The `labels`
-  element is mandatory. It needs to specify at least one language. Currently, "de", "en", "fr" and "it" are supported.
+  element is mandatory. It needs to specify at least one language. Currently, "de", "en", "fr", "it", and "rm" are supported.
 - _comments_: Comment with language tags in the form `{ "<lang>": "<comment>", "<lang>": "<comment>", ... }`.
-  Currently, "de", "en", "fr" and "it" are supported. The `comments` element is mandatory for the root node of the list.
+  Currently, "de", "en", "fr", "it", and "rm" are supported. The `comments` element is mandatory for the root node of the list.
   For all other nodes, it is optional. If not used, the element should be omitted.
 - _nodes_: Array of sub-nodes. The `nodes` element is optional and can be omitted in case of a flat list.
 
@@ -360,7 +360,7 @@ A group definition has the following elements:
 
 - _name_: name of the group, mandatory
 - _descriptions_: description of the group with language tags in the form `"descriptions": {"<lang>": "<string>", ...}` (
-  currently "en", "de", "fr" and "it" are supported), mandatory
+  currently "en", "de", "fr", "it", and "rm" are supported), mandatory
 - _selfjoin_: true if users are allowed to join the group themselves, false if an administrator has to add the users,
   optional
 - _status_: true if the group is active, false if the group is inactive, optional
diff --git a/knora/dsplib/models/group.py b/knora/dsplib/models/group.py
index 526f7e582..148eb2aa7 100644
--- a/knora/dsplib/models/group.py
+++ b/knora/dsplib/models/group.py
@@ -54,7 +54,7 @@ class Group(Model):
         Name of the group
 
     descriptions : LangString
-        Group descriptions in a given language (Languages.EN, Languages.DE, Languages.FR, Languages.IT).
+        Group descriptions in a given language (Languages.EN, Languages.DE, Languages.FR, Languages.IT, Languages.RM).
 
     project : str | project
         either the IRI of a project [get only, cannot be modified after creation of instance]
diff --git a/knora/dsplib/models/langstring.py b/knora/dsplib/models/langstring.py
index 72403d830..6ed6191c4 100644
--- a/knora/dsplib/models/langstring.py
+++ b/knora/dsplib/models/langstring.py
@@ -10,6 +10,7 @@ class Languages(Enum):
     DE = 'de'
     FR = 'fr'
     IT = 'it'
+    RM = 'rm'
 
 
 LangStringParam = Optional[Union[dict[Union[Languages, str], str], str]]
@@ -224,6 +225,8 @@ def fromJsonLdObj(cls, obj: Optional[Union[list[dict[str, str]], str]]) -> 'Lang
                 lstrs[Languages.FR] = o.get('@value')
             elif lang == 'it':
                 lstrs[Languages.IT] = o.get('@value')
+            elif lang == 'rm':
+                lstrs[Languages.RM] = o.get('@value')
             else:
                 if o.get('@value') is not None:
                     return cls(o.get('@value'))
@@ -250,6 +253,8 @@ def fromJsonObj(cls, obj: Optional[Any]) -> 'LangString':
                 lstrs[Languages.FR] = o.get('value')
             elif lang == 'it':
                 lstrs[Languages.IT] = o.get('value')
+            elif lang == 'rm':
+                lstrs[Languages.RM] = o.get('value')
             else:
                 if o.get('value') is not None:
                     return cls(o.get('value'))
diff --git a/knora/dsplib/schemas/lists-only.json b/knora/dsplib/schemas/lists-only.json
index c6904d351..a865a754f 100644
--- a/knora/dsplib/schemas/lists-only.json
+++ b/knora/dsplib/schemas/lists-only.json
@@ -7,7 +7,7 @@
         "langstring": {
             "type": "object",
             "patternProperties": {
-                "^(en|de|fr|it)": {
+                "^(en|de|fr|it|rm)$": {
                     "type": "string"
                 }
             },
@@ -19,7 +19,7 @@
         "comment": {
             "type": "object",
             "patternProperties": {
-                "^(en|de|fr|it)": {
+                "^(en|de|fr|it|rm)$": {
                     "type": "string"
                 }
             },
diff --git a/knora/dsplib/schemas/ontology.json b/knora/dsplib/schemas/ontology.json
index f05ce54fa..5a5829c1c 100644
--- a/knora/dsplib/schemas/ontology.json
+++ b/knora/dsplib/schemas/ontology.json
@@ -7,7 +7,7 @@
         "langstring": {
             "type": "object",
             "patternProperties": {
-                "^(en|de|fr|it)": {
+                "^(en|de|fr|it|rm)$": {
                     "type": "string"
                 }
             },
@@ -126,7 +126,7 @@
                 },
                 "lang": {
                     "type": "string",
-                    "pattern": "^(en|de|fr|it)"
+                    "pattern": "^(en|de|fr|it|rm)$"
                 },
                 "groups": {
                     "type": "array",
diff --git a/knora/dsplib/schemas/properties-only.json b/knora/dsplib/schemas/properties-only.json
index 71c36bd2f..0622af5aa 100644
--- a/knora/dsplib/schemas/properties-only.json
+++ b/knora/dsplib/schemas/properties-only.json
@@ -7,7 +7,7 @@
         "langstring": {
             "type": "object",
             "patternProperties": {
-                "^(en|de|fr|it)": {
+                "^(en|de|fr|it|rm)$": {
                     "type": "string"
                 }
             },
diff --git a/knora/dsplib/schemas/resources-only.json b/knora/dsplib/schemas/resources-only.json
index 06f803534..b80c0c74e 100644
--- a/knora/dsplib/schemas/resources-only.json
+++ b/knora/dsplib/schemas/resources-only.json
@@ -7,7 +7,7 @@
         "langstring": {
             "type": "object",
             "patternProperties": {
-                "^(en|de|fr|it)": {
+                "^(en|de|fr|it|rm)$": {
                     "type": "string"
                 }
             },
diff --git a/knora/dsplib/utils/excel_to_json_lists.py b/knora/dsplib/utils/excel_to_json_lists.py
index 7c23c3aeb..90f3b48f9 100644
--- a/knora/dsplib/utils/excel_to_json_lists.py
+++ b/knora/dsplib/utils/excel_to_json_lists.py
@@ -220,26 +220,6 @@ def simplify_name(value: str) -> str:
     return simplified_value
 
 
-def check_language_code(lang_code: str) -> bool:
-    """
-    Checks if a given language code is valid. The code is valid if it is listed in language-codes-3b2_csv.csv. This
-    file provides all ISO 639-1 and ISO 639-2 language codes.
-
-    Args:
-        lang_code: the language code to be checked
-
-    Returns:
-        True if valid, False if not
-    """
-    current_dir = os.path.dirname(os.path.realpath(__file__))
-    with open(os.path.join(current_dir, 'language-codes-3b2_csv.csv'), 'r') as language_codes_file:
-        language_codes = csv.reader(language_codes_file, delimiter=',')
-        for row in language_codes:
-            if lang_code in row:
-                return True
-    return False
-
-
 def make_root_node_from_args(
     excelfiles: list[str],
     listname_from_args: Optional[str],
@@ -264,9 +244,8 @@ def make_root_node_from_args(
         basename = os.path.basename(filename)
         lang_specific_listname, lang_code = os.path.splitext(basename)[0].rsplit('_', 1)
 
-        if not check_language_code(lang_code):
-            print(f'Invalid language code "{lang_code}" is used. Only language codes from ISO 639-1 ',
-                  f'and ISO 639-2 are accepted.')
+        if lang_code not in ['en', 'de', 'fr', 'it', 'rm']:
+            print(f'Invalid language code "{lang_code}" is used. Only en, de, fr, it, and rm are accepted.')
             quit()
 
         listname_from_lang_code[lang_code] = lang_specific_listname
diff --git a/knora/dsplib/utils/language-codes-3b2_csv.csv b/knora/dsplib/utils/language-codes-3b2_csv.csv
deleted file mode 100644
index 791eed085..000000000
--- a/knora/dsplib/utils/language-codes-3b2_csv.csv
+++ /dev/null
@@ -1,185 +0,0 @@
-ISO-639-2,ISO-639-1,English
-aar,aa,Afar
-abk,ab,Abkhazian
-afr,af,Afrikaans
-aka,ak,Akan
-alb,sq,Albanian
-amh,am,Amharic
-ara,ar,Arabic
-arg,an,Aragonese
-arm,hy,Armenian
-asm,as,Assamese
-ava,av,Avaric
-ave,ae,Avestan
-aym,ay,Aymara
-aze,az,Azerbaijani
-bak,ba,Bashkir
-bam,bm,Bambara
-baq,eu,Basque
-bel,be,Belarusian
-ben,bn,Bengali
-bih,bh,Bihari languages
-bis,bi,Bislama
-bos,bs,Bosnian
-bre,br,Breton
-bul,bg,Bulgarian
-bur,my,Burmese
-cat,ca,Catalan; Valencian
-cha,ch,Chamorro
-che,ce,Chechen
-chi,zh,Chinese
-chu,cu,Church Slavic; Old Slavonic; Church Slavonic; Old Bulgarian; Old Church Slavonic
-chv,cv,Chuvash
-cor,kw,Cornish
-cos,co,Corsican
-cre,cr,Cree
-cze,cs,Czech
-dan,da,Danish
-div,dv,Divehi; Dhivehi; Maldivian
-dut,nl,Dutch; Flemish
-dzo,dz,Dzongkha
-eng,en,English
-epo,eo,Esperanto
-est,et,Estonian
-ewe,ee,Ewe
-fao,fo,Faroese
-fij,fj,Fijian
-fin,fi,Finnish
-fre,fr,French
-fry,fy,Western Frisian
-ful,ff,Fulah
-geo,ka,Georgian
-ger,de,German
-gla,gd,Gaelic; Scottish Gaelic
-gle,ga,Irish
-glg,gl,Galician
-glv,gv,Manx
-gre,el,"Greek, Modern (1453-)"
-grn,gn,Guarani
-guj,gu,Gujarati
-hat,ht,Haitian; Haitian Creole
-hau,ha,Hausa
-heb,he,Hebrew
-her,hz,Herero
-hin,hi,Hindi
-hmo,ho,Hiri Motu
-hrv,hr,Croatian
-hun,hu,Hungarian
-ibo,ig,Igbo
-ice,is,Icelandic
-ido,io,Ido
-iii,ii,Sichuan Yi; Nuosu
-iku,iu,Inuktitut
-ile,ie,Interlingue; Occidental
-ina,ia,Interlingua (International Auxiliary Language Association)
-ind,id,Indonesian
-ipk,ik,Inupiaq
-ita,it,Italian
-jav,jv,Javanese
-jpn,ja,Japanese
-kal,kl,Kalaallisut; Greenlandic
-kan,kn,Kannada
-kas,ks,Kashmiri
-kau,kr,Kanuri
-kaz,kk,Kazakh
-khm,km,Central Khmer
-kik,ki,Kikuyu; Gikuyu
-kin,rw,Kinyarwanda
-kir,ky,Kirghiz; Kyrgyz
-kom,kv,Komi
-kon,kg,Kongo
-kor,ko,Korean
-kua,kj,Kuanyama; Kwanyama
-kur,ku,Kurdish
-lao,lo,Lao
-lat,la,Latin
-lav,lv,Latvian
-lim,li,Limburgan; Limburger; Limburgish
-lin,ln,Lingala
-lit,lt,Lithuanian
-ltz,lb,Luxembourgish; Letzeburgesch
-lub,lu,Luba-Katanga
-lug,lg,Ganda
-mac,mk,Macedonian
-mah,mh,Marshallese
-mal,ml,Malayalam
-mao,mi,Maori
-mar,mr,Marathi
-may,ms,Malay
-mlg,mg,Malagasy
-mlt,mt,Maltese
-mon,mn,Mongolian
-nau,na,Nauru
-nav,nv,Navajo; Navaho
-nbl,nr,"Ndebele, South; South Ndebele"
-nde,nd,"Ndebele, North; North Ndebele"
-ndo,ng,Ndonga
-nep,ne,Nepali
-nno,nn,"Norwegian Nynorsk; Nynorsk, Norwegian"
-nob,nb,"Bokmål, Norwegian; Norwegian Bokmål"
-nor,no,Norwegian
-nya,ny,Chichewa; Chewa; Nyanja
-oci,oc,Occitan (post 1500)
-oji,oj,Ojibwa
-ori,or,Oriya
-orm,om,Oromo
-oss,os,Ossetian; Ossetic
-pan,pa,Panjabi; Punjabi
-per,fa,Persian
-pli,pi,Pali
-pol,pl,Polish
-por,pt,Portuguese
-pus,ps,Pushto; Pashto
-que,qu,Quechua
-roh,rm,Romansh
-rum,ro,Romanian; Moldavian; Moldovan
-run,rn,Rundi
-rus,ru,Russian
-sag,sg,Sango
-san,sa,Sanskrit
-sin,si,Sinhala; Sinhalese
-slo,sk,Slovak
-slv,sl,Slovenian
-sme,se,Northern Sami
-smo,sm,Samoan
-sna,sn,Shona
-snd,sd,Sindhi
-som,so,Somali
-sot,st,"Sotho, Southern"
-spa,es,Spanish; Castilian
-srd,sc,Sardinian
-srp,sr,Serbian
-ssw,ss,Swati
-sun,su,Sundanese
-swa,sw,Swahili
-swe,sv,Swedish
-tah,ty,Tahitian
-tam,ta,Tamil
-tat,tt,Tatar
-tel,te,Telugu
-tgk,tg,Tajik
-tgl,tl,Tagalog
-tha,th,Thai
-tib,bo,Tibetan
-tir,ti,Tigrinya
-ton,to,Tonga (Tonga Islands)
-tsn,tn,Tswana
-tso,ts,Tsonga
-tuk,tk,Turkmen
-tur,tr,Turkish
-twi,tw,Twi
-uig,ug,Uighur; Uyghur
-ukr,uk,Ukrainian
-urd,ur,Urdu
-uzb,uz,Uzbek
-ven,ve,Venda
-vie,vi,Vietnamese
-vol,vo,Volapük
-wel,cy,Welsh
-wln,wa,Walloon
-wol,wo,Wolof
-xho,xh,Xhosa
-yid,yi,Yiddish
-yor,yo,Yoruba
-zha,za,Zhuang; Chuang
-zul,zu,Zulu
diff --git a/testdata/test-onto.json b/testdata/test-onto.json
index c865d1cb1..0ca42b17c 100644
--- a/testdata/test-onto.json
+++ b/testdata/test-onto.json
@@ -11,7 +11,8 @@
         "longname": "test project",
         "descriptions": {
             "en": "A systematic test project",
-            "de": "Ein systematisches Testprojekt"
+            "de": "Ein systematisches Testprojekt",
+            "rm": "Rumantsch descripziun"
         },
         "keywords": [
             "test",
@@ -21,17 +22,20 @@
             {
                 "name": "testlist",
                 "labels": {
-                    "en": "Testlist"
+                    "en": "Testlist",
+                    "rm": "Glista test in Rumantsch"
                 },
                 "comments": {
                     "en": "no comment",
-                    "de": "kein Kommentar"
+                    "de": "kein Kommentar",
+                    "rm": "nagin commentar in Rumantsch"
                 },
                 "nodes": [
                     {
                         "name": "a",
                         "labels": {
-                            "en": "a_label with a\"post'rophes"
+                            "en": "a_label with a\"post'rophes",
+                            "rm": "Rumantsch"
                         }
                     },
                     {
@@ -100,7 +104,8 @@
                 "name": "testgroupEditors",
                 "descriptions": {
                     "en": "Test group editors",
-                    "de": "Testgruppe Editors"
+                    "de": "Testgruppe Editors",
+                    "rm": "squadra test 'Editors' in Rumantsch"
                 },
                 "selfjoin": false,
                 "status": true
@@ -176,7 +181,8 @@
                         ],
                         "object": "TextValue",
                         "labels": {
-                            "en": "Text"
+                            "en": "Text",
+                            "rm": "hasTextChild2 in Rumantsch"
                         },
                         "gui_element": "SimpleText"
                     },
@@ -204,7 +210,8 @@
                         },
                         "comments": {
                             "en": "properties can optionally have comments",
-                            "de": "Properties können Kommentare haben"
+                            "de": "Properties können Kommentare haben",
+                            "rm": "Property with a Rumantsch comment"
                         },
                         "gui_element": "SimpleText",
                         "gui_attributes": {
@@ -391,7 +398,8 @@
                             "externalOnto:thing"
                         ],
                         "labels": {
-                            "en": "TestThing"
+                            "en": "TestThing",
+                            "rm": "TestThing in Rumantsch"
                         },
                         "cardinalities": [
                             {
@@ -520,7 +528,8 @@
                             "en": "A Compound Thing"
                         },
                         "comments": {
-                            "en": "A thing for testing compound things."
+                            "en": "A thing for testing compound things.",
+                            "rm": "Rumantsch comment of resource 'CompoundThing'"
                         },
                         "cardinalities": [
                             {