diff --git a/common/main/pms.xml b/common/main/pms.xml
new file mode 100644
index 00000000000..4b2226dbc5c
--- /dev/null
+++ b/common/main/pms.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<!DOCTYPE ldml SYSTEM "../../common/dtd/ldml.dtd">
+<!-- Copyright © 1991-2025 Unicode, Inc.
+For terms of use, see http://www.unicode.org/copyright.html
+SPDX-License-Identifier: Unicode-3.0
+CLDR data files are interpreted according to the LDML specification (http://unicode.org/reports/tr35/)
+-->
+<ldml>
+	<identity>
+		<version number="$Revision$"/>
+		<language type="pms"/>
+	</identity>
+	<localeDisplayNames>
+		<languages>
+			<language type="pms">piemontèis</language>
+		</languages>
+	</localeDisplayNames>
+	<characters>
+		<exemplarCharacters>[aà b c {ch} {cc} d eèéë {eu} f g {gh} {gg} iì j l m n {n-} oò p q r s {ss} {s-c} t uù v z]</exemplarCharacters>
+		<exemplarCharacters type="auxiliary">[h]</exemplarCharacters>
+		<exemplarCharacters type="numbers">↑↑↑</exemplarCharacters>
+		<exemplarCharacters type="punctuation">[\- ‑ — , ; \: ! ? . … '’ &quot;“” « » ( ) \[ \] \{ \} @ /]</exemplarCharacters>
+	</characters>
+</ldml>
diff --git a/common/main/pms_IT.xml b/common/main/pms_IT.xml
new file mode 100644
index 00000000000..58a7a0eb1e4
--- /dev/null
+++ b/common/main/pms_IT.xml
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<!DOCTYPE ldml SYSTEM "../../common/dtd/ldml.dtd">
+<!-- Copyright © 1991-2024 Unicode, Inc.
+For terms of use, see http://www.unicode.org/copyright.html
+SPDX-License-Identifier: Unicode-3.0
+CLDR data files are interpreted according to the LDML specification (http://unicode.org/reports/tr35/)
+-->
+<ldml>
+	<identity>
+		<version number="$Revision$"/>
+		<language type="pms"/>
+		<territory type="IT"/>
+	</identity>
+</ldml>
diff --git a/common/supplemental/supplementalData.xml b/common/supplemental/supplementalData.xml
index 95665e64e04..4c0a171daf5 100644
--- a/common/supplemental/supplementalData.xml
+++ b/common/supplemental/supplementalData.xml
@@ -3423,6 +3423,7 @@ XXX Code for transations where no currency is involved
 			<languagePopulation type="sc" populationPercent="1.7"/>	<!--Sardinian-->
 			<languagePopulation type="de" populationPercent="1.6" references="R1251"/>	<!--German-->
 			<languagePopulation type="vec" populationPercent="1.3" officialStatus="official_regional" references="R1295"/>	<!--Venetian-->
+			<languagePopulation type="pms" populationPercent="1.1" references="R1041"/>	<!--Piedmontese-->
 			<languagePopulation type="nap" writingPercent="5" populationPercent="0.97" references="R1148"/>	<!--Neapolitan-->
 			<languagePopulation type="lij" populationPercent="0.86"/>	<!--Ligurian-->
 			<languagePopulation type="scn" writingPercent="5" populationPercent="0.82" references="R1149"/>	<!--Sicilian-->
@@ -3433,7 +3434,6 @@ XXX Code for transations where no currency is involved
 			<languagePopulation type="lld" populationPercent="0.048" references="R1249"/>	<!--Ladin-->
 			<languagePopulation type="ca" populationPercent="0.035"/>	<!--Catalan-->
 			<languagePopulation type="el" populationPercent="0.035"/>	<!--Greek-->
-			<languagePopulation type="pms" populationPercent="0.01"/>	<!--Piedmontese-->
 			<languagePopulation type="hr" populationPercent="0.0057"/>	<!--Croatian-->
 			<languagePopulation type="mhn" populationPercent="0.0023"/>	<!--Mócheno-->
 			<languagePopulation type="rgn" populationPercent="0" references="R1150"/>	<!--Romagnol-->
@@ -5574,6 +5574,7 @@ XXX Code for transations where no currency is involved
 		<reference type="R1037" uri="http://en.wikipedia.org/wiki/Kiribati">English official; Kiribati widespread</reference>
 		<reference type="R1038" uri="https://www.cia.gov/cia/publications/factbook/fields/2098.html">[missing]</reference>
 		<reference type="R1039" uri="https://www.cia.gov/cia/publications/factbook/geos/ls.html">German official</reference>
+		<reference type="R1041">Regis, Riccardo. &quot;Su pianificazione, standardizzazione, polinomia: due esempi&quot; Zeitschrift für romanische Philologie, vol. 128, no. 1, 2012, pp. 88-133.</reference>
 		<reference type="R1042" uri="https://www.cia.gov/cia/publications/factbook/geos/nl.html">Used CIA literacy figure times population, added 'Vlaams' population</reference>
 		<reference type="R1043" uri="http://www.cso.ie/census/documents/Final%20Principal%20Demographic%20Results%202006.pdf">[missing]</reference>
 		<reference type="R1044" uri="http://www.ethnologue.com/show_language.asp?code=mri">70,000 in 1991, 100,000 who understand it, but do not speak it ; ethnic pop 530,000 in 2002</reference>
diff --git a/common/testData/localeIdentifiers/localeDisplayName.txt b/common/testData/localeIdentifiers/localeDisplayName.txt
index 2db23c892e0..4240a2ade36 100644
--- a/common/testData/localeIdentifiers/localeDisplayName.txt
+++ b/common/testData/localeIdentifiers/localeDisplayName.txt
@@ -2366,7 +2366,7 @@ zh-Hans-fonipa; zh (Hans, FONIPA)
 
 en-MM; en (MM)
 es; es
-es-419; es_419
+es-419; es (419)
 es-Cyrl-MX; es (Cyrl, MX)
 hi-Latn; hi (Latn)
 nl-BE; nl (BE)
@@ -3204,4 +3204,3 @@ hi-Latn; isi-Hindi (isi-Latin)
 nl-BE; isi-Flemish
 nl-Latn-BE; isi-Flemish (isi-Latin)
 zh-Hans-fonipa; isi-Chinese [esenziwe-lula] (Ifonotiki ye-IPA)
-
diff --git a/tools/cldr-code/src/main/resources/org/unicode/cldr/util/data/country_language_population.tsv b/tools/cldr-code/src/main/resources/org/unicode/cldr/util/data/country_language_population.tsv
index f0fb1df2b00..aab2f4bf51c 100644
--- a/tools/cldr-code/src/main/resources/org/unicode/cldr/util/data/country_language_population.tsv
+++ b/tools/cldr-code/src/main/resources/org/unicode/cldr/util/data/country_language_population.tsv
@@ -706,7 +706,7 @@ Italy	IT	"62,246,674"	99%	"2,317,000,000,000"	official	Italian	it	95%
 Italy	IT	"62,246,674"	99%	"2,317,000,000,000"		Ligurian	lij	"535,000"
 Italy	IT	"62,246,674"	99%	"2,317,000,000,000"		Lombard	lmo	"3,530,000"			"https://en.wikipedia.org/wiki/Lombard_language#Usage but subtracting 270,000 per https://en.wikipedia.org/wiki/Swiss_Italian"
 Italy	IT	"62,246,674"	99%	"2,317,000,000,000"		Neapolitan	nap	"603,000"	5%		5% writing pop estimated in absence of other data; literacy rate reported at 12%
-Italy	IT	"62,246,674"	99%	"2,317,000,000,000"		Piedmontese	pms	"6,170"
+Italy	IT	"62,246,674"	99%	"2,317,000,000,000"		Piedmontese	pms	"700,000"			Regis, Riccardo. "Su pianificazione, standardizzazione, polinomia: due esempi" Zeitschrift für romanische Philologie, vol. 128, no. 1, 2012, pp. 88-133.
 Italy	IT	"62,246,674"	99%	"2,317,000,000,000"		Romagnol	rgn	1			No estimate available.
 Italy	IT	"62,246,674"	99%	"2,317,000,000,000"	recognized	Sardinian	sc	"1,060,000"
 Italy	IT	"62,246,674"	99%	"2,317,000,000,000"		Sassarese Sardinian	sdc	"107,000"