[Ietf-languages] Proposed forms for Serbo-Croatian and related languages

[Doug Ewell <[e-mail]>]

This may not have been the outcome that Winston Sung expected, but yes, we do need to do the same thing for sh → hbs.

Below are proposed records and registration forms to:

• add a new language subtag 'hbs' for Serbo-Croatian
• deprecate 'sh' with a Preferred-Value of 'hbs'
• update the Macrolanguage fields of 'bs', 'hr', 'sr', and 'cnr'
• slightly update the Comments field for now-deprecated 'sh'

How did 'bs' and the others get involved in this?

Code element [hbs] for Serbo-Croatian in Set 3 is a macrolanguage, encompassing Bosnian, Croatian, Serbian, and Montenegrin. Those individual languages have had a "Macrolanguage: sh" field since 2009, when RFCs 5646 and 5645 and the revised Registry were introduced, adding ISO 639-3 and the notion of macrolanguages. (Montenegrin was added in 2018 and has always had "Macrolanguage: sh".)

During development of RFC 5646, it became clear that it was desirable to avoid what we called “chained Preferred-Values,” as described in Section 3.1.7:

“Changes to one subtag can affect other subtags as well: when proposing changes to the registry, the Language Subtag Reviewer MUST review the registry for such effects and propose the necessary changes using the process in Section 3.5, although anyone MAY request such changes.  For example:

“Suppose that subtag 'XX' has a 'Preferred-Value' of 'YY'.  If 'YY' later changes to have a 'Preferred-Value' of 'ZZ', then the 'Preferred-Value' for 'XX' MUST also change to be 'ZZ'.”

We are now in the same situation, but with regard to Macrolanguage fields instead of Preferred-Value fields. It would not make sense for (say) Bosnian 'bs' to have a Macrolanguage field of 'sh', which will now be deprecated, forcing people or processes to “follow the chain” to arrive at the new subtag 'hbs'. Therefore, these four encompassed languages need to be updated as well.

The update to the Comments field of 'sh' is very minor:

“Comments: sr, hr, bs are preferred for most modern uses”

should be updated to include 'cnr' for Montenegrin, which again did not exist as a subtag until 2018. Making this change for a deprecated subtag isn’t strictly required (we could as well just remove the comment), but might reduce a bit of confusion.

Please send all comments to the list. (My thanks to Winston for his comment that called attention to the need for these changes.) The review period ends the same day as for the Bihari changes: Sunday, May 24, 2026.

---

LANGUAGE SUBTAG MODIFICATION
File-Date: 2026-xx-xx
%%
Type: language
Subtag: sh
Description: Serbo-Croatian
Added: 2005-10-16
Deprecated: 2026-xx-xx
Preferred-Value: hbs
Scope: macrolanguage
Comments: sr, hr, bs, cnr are preferred for most modern uses
%%

---

LANGUAGE SUBTAG REGISTRATION FORM

1. Name of requester: Doug Ewell
2. E-mail address of requester: doug at ewellic.org

3. Record Requested:

Type: language
Subtag: sh
Description: Serbo-Croatian
Deprecated: 2026-xx-xx
Preferred-Value: hbs
Scope: macrolanguage
Comments: sr, hr, bs, cnr are preferred for most modern uses

4. Intended meaning of the subtag:

5. Reference to published description of the language (book or article):

6. Any other relevant information:

This registration tracks a change made to ISO 639-1 (now ISO 639 Set 1)
effective 2000-02-18, withdrawing [sh] for "Serbo-Croatian" in favor of
code elements for the individual languages [bs], [hr], and [sr]. The Set
3 macrolanguage [hbs] has the same denotation as [sh]; subtag 'sh' is
deprecated in the Registry and subtag 'hbs' is added to replace it.

The Comments field for the deprecated 'sh' is also updated to include
'cnr'.

For more information on the ISO 639 change, refer to:
https://www.loc.gov/standards/iso639-2/php/code_changes.php

---

LANGUAGE SUBTAG MODIFICATION
File-Date: 2026-xx-xx
%%
Type: language
Subtag: hbs
Description: Serbo-Croatian
Added: 2026-xx-xx
Scope: macrolanguage
Comments: sr, hr, bs, cnr are preferred for most modern uses
%%

---

LANGUAGE SUBTAG REGISTRATION FORM

1. Name of requester: Doug Ewell
2. E-mail address of requester: doug at ewellic.org

3. Record Requested:

Type: language
Subtag: hbs
Description: Serbo-Croatian
Scope: macrolanguage
Comments: sr, hr, bs, cnr are preferred for most modern uses

4. Intended meaning of the subtag:

5. Reference to published description of the language (book or article):

6. Any other relevant information:

This registration tracks a change made to ISO 639-1 (now ISO 639 Set 1)
effective 2000-02-18, withdrawing [sh] for "Serbo-Croatian" in favor of
code elements for the individual languages [bs], [hr], and [sr]. The Set
3 macrolanguage [hbs] has the same denotation as [sh]; subtag 'sh' is
deprecated in the Registry and subtag 'hbs' is added to replace it.

For more information on the ISO 639 change, refer to:
https://www.loc.gov/standards/iso639-2/php/code_changes.php

---

LANGUAGE SUBTAG MODIFICATION
File-Date: 2026-xx-xx
%%
Type: language
Subtag: bs
Description: Bosnian
Added: 2005-10-16
Suppress-Script: Latn
Macrolanguage: hbs
%%

---

LANGUAGE SUBTAG REGISTRATION FORM

1. Name of requester: Doug Ewell
2. E-mail address of requester: doug at ewellic.org

3. Record Requested:

Type: language
Subtag: bs
Description: Bosnian
Suppress-Script: Latn
Macrolanguage: hbs

4. Intended meaning of the subtag:

5. Reference to published description of the language (book or article):

6. Any other relevant information:

This registration tracks a change made to ISO 639-1 (now ISO 639 Set 1)
effective 2000-02-18, withdrawing [sh] for "Serbo-Croatian" in favor of
code elements for the individual languages [bs], [hr], and [sr]. The Set
3 macrolanguage [hbs] has the same denotation as [sh]; subtag 'sh' is
deprecated in the Registry and subtag 'hbs' is added to replace it.

The Macrolanguage fields for subtags 'bs' (Bosnian), 'hr' (Croatian),
'sr' (Serbian), and 'cnr' (Montenegrin) are updated from 'sh' to 'hbs'.

For more information on the ISO 639 change, refer to:
https://www.loc.gov/standards/iso639-2/php/code_changes.php

---

LANGUAGE SUBTAG MODIFICATION
File-Date: 2026-xx-xx
%%
Type: language
Subtag: hr
Description: Croatian
Added: 2005-10-16
Suppress-Script: Latn
Macrolanguage: hbs
%%

---

LANGUAGE SUBTAG REGISTRATION FORM

1. Name of requester: Doug Ewell
2. E-mail address of requester: doug at ewellic.org

3. Record Requested:

Type: language
Subtag: hr
Description: Croatian
Suppress-Script: Latn
Macrolanguage: hbs

4. Intended meaning of the subtag:

5. Reference to published description of the language (book or article):

6. Any other relevant information:

This registration tracks a change made to ISO 639-1 (now ISO 639 Set 1)
effective 2000-02-18, withdrawing [sh] for "Serbo-Croatian" in favor of
code elements for the individual languages [bs], [hr], and [sr]. The Set
3 macrolanguage [hbs] has the same denotation as [sh]; subtag 'sh' is
deprecated in the Registry and subtag 'hbs' is added to replace it.

The Macrolanguage fields for subtags 'bs' (Bosnian), 'hr' (Croatian),
'sr' (Serbian), and 'cnr' (Montenegrin) are updated from 'sh' to 'hbs'.

For more information on the ISO 639 change, refer to:
https://www.loc.gov/standards/iso639-2/php/code_changes.php

---

LANGUAGE SUBTAG MODIFICATION
File-Date: 2026-xx-xx
%%
Type: language
Subtag: sr
Description: Serbian
Added: 2005-10-16
Macrolanguage: hbs
Comments: see cnr for Montenegrin
%%

---

LANGUAGE SUBTAG REGISTRATION FORM

1. Name of requester: Doug Ewell
2. E-mail address of requester: doug at ewellic.org

3. Record Requested:

Type: language
Subtag: sr
Description: Serbian
Macrolanguage: hbs
Comments: see cnr for Montenegrin

4. Intended meaning of the subtag:

5. Reference to published description of the language (book or article):

6. Any other relevant information:

This registration tracks a change made to ISO 639-1 (now ISO 639 Set 1)
effective 2000-02-18, withdrawing [sh] for "Serbo-Croatian" in favor of
code elements for the individual languages [bs], [hr], and [sr]. The Set
3 macrolanguage [hbs] has the same denotation as [sh]; subtag 'sh' is
deprecated in the Registry and subtag 'hbs' is added to replace it.

The Macrolanguage fields for subtags 'bs' (Bosnian), 'hr' (Croatian),
'sr' (Serbian), and 'cnr' (Montenegrin) are updated from 'sh' to 'hbs'.

For more information on the ISO 639 change, refer to:
https://www.loc.gov/standards/iso639-2/php/code_changes.php

---

LANGUAGE SUBTAG MODIFICATION
File-Date: 2026-xx-xx
%%
Type: language
Subtag: cnr
Description: Montenegrin
Added: 2018-01-23
Macrolanguage: hbs
Comments: see sr for Serbian
%%

---

LANGUAGE SUBTAG REGISTRATION FORM

1. Name of requester: Doug Ewell
2. E-mail address of requester: doug at ewellic.org

3. Record Requested:

Type: language
Subtag: cnr
Description: Montenegrin
Macrolanguage: hbs
Comments: see sr for Serbian

4. Intended meaning of the subtag:

5. Reference to published description of the language (book or article):

6. Any other relevant information:

This registration tracks a change made to ISO 639-1 (now ISO 639 Set 1)
effective 2000-02-18, withdrawing [sh] for "Serbo-Croatian" in favor of
code elements for the individual languages [bs], [hr], and [sr]. The Set
3 macrolanguage [hbs] has the same denotation as [sh]; subtag 'sh' is
deprecated in the Registry and subtag 'hbs' is added to replace it.

The Macrolanguage fields for subtags 'bs' (Bosnian), 'hr' (Croatian),
'sr' (Serbian), and 'cnr' (Montenegrin) are updated from 'sh' to 'hbs'.

For more information on the ISO 639 change, refer to:
https://www.loc.gov/standards/iso639-2/php/code_changes.php


--
Doug Ewell, CC, ALB | Lakewood, CO, US | ewellic.org