diff --git a/IANA_languages.js b/IANA_languages.js
index 9c35d08..dc80957 100644
--- a/IANA_languages.js
+++ b/IANA_languages.js
@@ -1,6 +1,6 @@
 /**
  * IANA_languages.js
- * 
+ *
  * Load and check language identifiers
  */
 import { readFile, readFileSync } from "fs";
@@ -46,6 +46,9 @@ export default class IANAlanguages {
 	stats(res) {
 		res.numLanguages = this.#languagesList.length;
 		res.numRedundantLanguages = this.#redundantLanguagesList.length;
+		let t = [];
+		this.#redundantLanguagesList.forEach((e) => t.push(`${e.tag}${e.preferred ? `~${e.preferred}` : ""}`));
+		res.RedundantLanguages = t.join(", ");
 		res.numLanguageRanges = this.#languageRanges.length;
 		res.numSignLanguages = this.#signLanguagesList.length;
 		if (this.#languageFileDate) res.languageFileDate = this.#languageFileDate;
@@ -66,9 +69,7 @@ export default class IANAlanguages {
 		 * @return {boolean} true if the language subtag is a sign language
 		 */
 		function isSignLanguage(items) {
-			for (let i = 0; i < items.length; i++)
-				 if (items[i].startsWith("Description") && items[i].toLowerCase().includes("sign")) 
-						return true;
+			for (let i = 0; i < items.length; i++) if (items[i].startsWith("Description") && items[i].toLowerCase().includes("sign")) return true;
 			return false;
 		}
 
@@ -141,9 +142,8 @@ export default class IANAlanguages {
 					} else console.log(chalk.red(`error loading languages ${err}`));
 				}.bind(this)
 			);
-		}
-		else {
-			let langs = readFileSync(languagesFile, { encoding: "utf-8" } ).toString();
+		} else {
+			let langs = readFileSync(languagesFile, { encoding: "utf-8" }).toString();
 			this.#processLanguageData(langs);
 		}
 	}
@@ -161,7 +161,7 @@ export default class IANAlanguages {
 
 		if (purge) this.empty();
 
-		if (async) 
+		if (async)
 			fetch(languagesURL)
 				.then(handleErrors)
 				.then((response) => response.text())
@@ -175,14 +175,13 @@ export default class IANAlanguages {
 				console.log(chalk.red(error.message));
 			}
 			if (resp) {
-				if (resp.ok) 
-					this.#processLanguageData(response.text);
-				else console.log(chalk.red(`error (${error}) retrieving ${languagesURL}`));
+				if (resp.ok) this.#processLanguageData(resp.text);
+				else console.log(chalk.red(`error (${resp.error}) retrieving ${languagesURL}`));
 			}
 		}
 	}
 
-	loadLanguages(options, async=true) {
+	loadLanguages(options, async = true) {
 		if (!options) options = {};
 		if (!Object.prototype.hasOwnProperty.call(options, "purge")) options.purge = false;
 
@@ -202,6 +201,13 @@ export default class IANAlanguages {
 		if (datatypeIs(value, "string")) {
 			if (this.#languageRanges.find((range) => range.start <= value && value <= range.end)) return { resp: this.languageKnown };
 
+			let found = this.#redundantLanguagesList.find((e) => e.tag.toLowerCase() == value.toLowerCase());
+			if (found) {
+				let res = { resp: this.languageRedundant };
+				if (found?.preferred) res.pref = found.preferred;
+				return res;
+			}
+
 			if (value.indexOf("-") != -1) {
 				let matches = true;
 				let parts = value.split("-");
@@ -213,15 +219,6 @@ export default class IANAlanguages {
 
 			if (isIni(this.#languagesList, value)) return { resp: this.languageKnown };
 
-			let lc = value.toLowerCase();
-			let found = this.#redundantLanguagesList.find((e) => e.tag.toLowerCase() == lc);
-			if (found) {
-				let res = { resp: this.languageRedundant };
-				if (found?.preferred) res.pref = found.preferred;
-				[];
-				return res;
-			}
-
 			return { resp: this.languageUnknown };
 		}
 		return { resp: this.languageInvalidType };
diff --git a/accessibility_attributes_checks.js b/accessibility_attributes_checks.js
index d820b9b..25e5990 100644
--- a/accessibility_attributes_checks.js
+++ b/accessibility_attributes_checks.js
@@ -1,7 +1,7 @@
 /**
  * accessibility_attribites_checks.js
- * 
- * Checks the value space of the <AccessibilityAttributes> element against the rules and 
+ *
+ * Checks the value space of the <AccessibilityAttributes> element against the rules and
  * values provided in DVB A177.
  */
 import { datatypeIs } from "./phlib/phlib.js";
@@ -13,6 +13,7 @@ import { APPLICATION, WARNING } from "./error_list.js";
 import { checkTopElementsAndCardinality } from "./schema_checks.js";
 import { CS_URI_DELIMITER } from "./classification_scheme.js";
 
+import { DumpString } from "./utils.js";
 
 export function CheckAccessibilityAttributes(AccessibilityAttributes, cs, errs, errCode) {
 	const ACCESSIBILITY_CHECK_KEY = "accessibility attributes";
@@ -126,23 +127,27 @@ export function CheckAccessibilityAttributes(AccessibilityAttributes, cs, errs,
 	};
 
 	let checkCS = (elem, childName, cs, errNum, storage = null) => {
-		let children = elem.childNodes();
+		let rc = true,
+			children = elem.childNodes();
 		if (children)
 			children.forEachSubElement((e) => {
 				if (e.name() == childName) {
 					let href = e.attr(tva.a_href) ? e.attr(tva.a_href).value() : null;
-					if (href && !cs.isIn(href))
+					if (href && !cs.isIn(href)) {
 						errs.addError({
 							code: `${errCode}-${errNum}`,
 							fragment: e,
 							message: `"${href}" is not valid for ${e.name().elementize()} in ${elem.name().elementize()}`,
 							key: ACCESSIBILITY_CHECK_KEY,
 						});
+						rc = false;
+					}
 					if (storage && datatypeIs(storage, "array") && href) {
 						storage.push(href);
 					}
 				}
 			});
+		return rc;
 	};
 
 	let checkSignLanguage = (elem, childName, errNum) => {
@@ -150,13 +155,31 @@ export function CheckAccessibilityAttributes(AccessibilityAttributes, cs, errs,
 		if (children)
 			children.forEachSubElement((e) => {
 				if (e.name() == childName) {
-					if (cs.KnownLanguages.checkSignLanguage(e.text()) != cs.KnownLanguages.languageKnown)
+					let languageCode = e.text();
+					let lState = cs.KnownLanguages.isKnown(languageCode);
+					if (lState.resp == cs.KnownLanguages.languageRedundant) {
 						errs.addError({
-							code: `${errCode}-${errNum}`,
+							code: `${errCode}-${errNum}a`,
+							fragment: e,
+							message: `sign language ${languageCode.quote()} is redundant${lState.pref ? `, use ${lState.pref.quote()} instead` : ""}`,
+							key: "deprecated language",
+							type: WARNING,
+						});
+						if (lState.pref) languageCode = lState.pref;
+					}
+
+					if (cs.KnownLanguages.checkSignLanguage(languageCode) != cs.KnownLanguages.languageKnown) {
+						errs.addError({
+							code: `${errCode}-${errNum}b`,
 							fragment: e,
-							message: `"${e.text()}" is not a valid sign language for ${e.name().elementize()} in ${elem.name().elementize()}`,
+							message: `${languageCode.quote()} is not a valid sign language for ${e.name().elementize()} in ${elem.name().elementize()}`,
 							key: ACCESSIBILITY_CHECK_KEY,
 						});
+						errs.errorDescription({
+							code: `${errCode}-${errNum}b`,
+							description: `language used for ${e.name().elementize()}} must be a sign language in the IANA language-subtag-regostry`,
+						});
+					}
 				}
 			});
 	};
@@ -323,7 +346,8 @@ export function CheckAccessibilityAttributes(AccessibilityAttributes, cs, errs,
 						`${errCode}-71`
 					);
 					checkAppInformation(elem, 72);
-					checkCS(elem, tva.e_Coding, cs.VideoCodecCS, 73);
+					if (!checkCS(elem, tva.e_Coding, cs.VideoCodecCS, 73))
+						errs.errorDescription({ code: `${errCode}-73`, description: `value for ${tva.e_Coding.elementize()} is not taken from the VideoCodecCS` });
 					checkSignLanguage(elem, tva.e_SignLanguage, 74);
 					break;
 				case tva.e_DialogueEnhancementAttributes:
diff --git a/cg_check.js b/cg_check.js
index 405a853..db07503 100644
--- a/cg_check.js
+++ b/cg_check.js
@@ -1274,12 +1274,14 @@ export default class ContentGuideCheck {
 			const titleLang = GetNodeLanguage(Title, false, errs, `${errCode}-2`, this.#knownLanguages);
 			const titleStr = unEntity(Title.text());
 
-			if (titleStr.length > dvbi.MAX_TITLE_LENGTH)
+			if (titleStr.length > dvbi.MAX_TITLE_LENGTH) {
 				errs.addError({
 					code: `${errCode}-11`,
 					message: `${tva.e_Title.elementize()} length exceeds ${dvbi.MAX_TITLE_LENGTH} characters`,
 					fragment: Title,
 				});
+				errs.errorDescription({code:`${errCode}-11`, description: "refer clause 6.10.5 in A177"})
+			}
 			switch (titleType) {
 				case mpeg7.TITLE_TYPE_MAIN:
 					if (mainTitles.find((e) => e.lang == titleLang))
@@ -1310,6 +1312,8 @@ export default class ContentGuideCheck {
 						message: `${tva.a_type.attribute()} must be ${mpeg7.TITLE_TYPE_MAIN.quote()} or ${mpeg7.TITLE_TYPE_SECONDARY.quote()} for ${tva.e_Title.elementize()}`,
 						fragment: Title,
 					});
+					errs.errorDescription({code:`${errCode}-15`, description: "refer to the relevant subsection of clause 6.10.5 in A177"});
+					break;
 			}
 		}
 		secondaryTitles.forEach((item) => {
@@ -1522,6 +1526,12 @@ export default class ContentGuideCheck {
 		}
 	}
 
+	/*private*/ #NotCRIDFormat(errs, error)
+	{
+		errs.addError(error);
+		errs.errorDescription({code: error?.code, description: "format if a CRID is defined in clause 8 of ETSI TS 102 822"})
+	}
+
 	/**
 	 * validate the <ProgramInformation> element against the profile for the given request/response type
 	 *
@@ -1573,7 +1583,7 @@ export default class ContentGuideCheck {
 		if (ProgramInformation.attr(tva.a_programId)) {
 			programCRID = ProgramInformation.attr(tva.a_programId).value();
 			if (!isCRIDURI(programCRID))
-				errs.addError({
+				this.#NotCRIDFormat(errs, {
 					code: "PI011",
 					message: `${tva.a_programId.attribute(ProgramInformation.name())} is not a valid CRID (${programCRID})`,
 					line: ProgramInformation.line(),
@@ -1617,7 +1627,7 @@ export default class ContentGuideCheck {
 									fragment: child,
 								});
 							else if (!isCRIDURI(foundCRID))
-								errs.addError({
+								this.#NotCRIDFormat(errs, {
 									code: "PI033",
 									message: `${tva.a_crid.attribute(`${ProgramInformation.name()}.${tva.e_EpisodeOf}`)}=${foundCRID.quote()} is not a valid CRID`,
 									fragment: child,
@@ -1652,7 +1662,7 @@ export default class ContentGuideCheck {
 									fragment: child,
 								});
 							else if (!isCRIDURI(foundCRID))
-								errs.addError({
+								this.#NotCRIDFormat(errs,{
 									code: "PI045",
 									message: `${tva.a_crid.attribute(`${ProgramInformation.name()}.${tva.e_MemberOf}`)}=${foundCRID.quote()} is not a valid CRID`,
 									fragment: child,
@@ -1951,7 +1961,7 @@ export default class ContentGuideCheck {
 		if (GroupInformation.attr(tva.a_groupId)) {
 			const groupId = GroupInformation.attr(tva.a_groupId).value();
 			if (!isCRIDURI(groupId))
-				errs.addError({
+				this.#NotCRIDFormat(errs, {
 					code: "GIM003",
 					message: `${tva.a_groupId.attribute(GroupInformation.name())} value ${groupId.quote()} is not a valid CRID`,
 					line: GroupInformation.line(),
@@ -2974,12 +2984,13 @@ export default class ContentGuideCheck {
 
 				let ProgramCRID = Program.attr(tva.a_crid);
 				if (ProgramCRID) {
-					if (!isCRIDURI(ProgramCRID.value()))
-						errs.addError({
+					if (!isCRIDURI(ProgramCRID.value())) {
+						this.#NotCRIDFormat(errs, {
 							code: "SE011",
 							message: `${tva.a_crid.attribute(tva.e_Program)} is not a valid CRID (${ProgramCRID.value()})`,
 							fragment: Program,
 						});
+					}
 					if (!isIni(programCRIDs, ProgramCRID.value()))
 						errs.addError({
 							code: "SE012",
diff --git a/sl_check.js b/sl_check.js
index 987c296..5a598d6 100644
--- a/sl_check.js
+++ b/sl_check.js
@@ -1,13 +1,11 @@
 /**
  * sl_check.js
- * 
+ *
  * Check a service list
  */
 import { readFileSync } from "fs";
 import process from "process";
 
-
-
 import chalk from "chalk";
 import { parseXmlString } from "libxmljs2";
 
@@ -384,7 +382,7 @@ export default class ServiceListCheck {
 	#allowedVideoConformancePoints;
 	#RecordingInfoCSvalues;
 
-	constructor(useURLs, opts, async=true) {
+	constructor(useURLs, opts, async = true) {
 		this.#numRequests = 0;
 
 		this.#knownLanguages = opts?.languages ? opts.languages : LoadLanguages(useURLs, async);
@@ -419,7 +417,6 @@ export default class ServiceListCheck {
 		});
 	}
 
-
 	stats() {
 		let res = {};
 		res.numRequests = this.#numRequests;
@@ -1347,9 +1344,7 @@ export default class ServiceListCheck {
 					if (nestedCAsystemid) {
 						CASystemID_value = nestedCAsystemid.text();
 					}
-				} 
-				else 
-					CASystemID_value = CASystemID.text();
+				} else CASystemID_value = CASystemID.text();
 				if (CASystemID_value) {
 					let CASid_value = parseInt(CASystemID_value, 10);
 					if (isNaN(CASid_value)) {
@@ -1385,8 +1380,7 @@ export default class ServiceListCheck {
 					if (nestedDRMsystemid) {
 						DRMSystemID_value = nestedDRMsystemid.text().toLowerCase();
 					}
-				} 
-				else DRMSystemID_value = DRMSystemID.text().toLowerCase();
+				} else DRMSystemID_value = DRMSystemID.text().toLowerCase();
 				if (DRMSystemID_value && ContentProtectionIDs.find((el) => el.id == DRMSystemID_value || el.id.substring(el.id.lastIndexOf(":") + 1) == DRMSystemID_value) == undefined) {
 					errs.addError({
 						code: "SI033",
@@ -1781,7 +1775,7 @@ export default class ServiceListCheck {
 							fragment: element,
 						});
 				};
-				let DisallowedElement = (element, childElementName, modulation, suffix="-0") => {
+				let DisallowedElement = (element, childElementName, modulation, suffix = "-0") => {
 					if (hasChild(element, childElementName))
 						errs.addError({
 							code: `SI204${suffix}`,
@@ -1805,7 +1799,7 @@ export default class ServiceListCheck {
 						checkElement(ModulationType, dvbi.e_ModulationType, sats.S2_Modulation, sats.MODULATION_S2, "SI202b");
 						checkElement(FEC, dvbi.e_FEC, sats.S2_FEC, sats.MODULATION_S2, "SI203b");
 						DisallowedElement(DVBSDeliveryParameters, dvbi.e_ModcodMode, sats.MODULATION_S2, "k");
-						DisallowedElement(DVBSDeliveryParameters, dvbi.e_InputStreamIdentifier, sats.MODULATION_S2, 'l');
+						DisallowedElement(DVBSDeliveryParameters, dvbi.e_InputStreamIdentifier, sats.MODULATION_S2, "l");
 						DisallowedElement(DVBSDeliveryParameters, dvbi.e_ChannelBonding, sats.MODULATION_S2, "m");
 						break;
 					case sats.MODULATION_S2X:
@@ -1959,13 +1953,15 @@ export default class ServiceListCheck {
 		let uID = service.get(xPath(props.prefix, dvbi.e_UniqueIdentifier), props.schema);
 		if (uID) {
 			thisServiceId = uID.text();
-			if (!validServiceIdentifier(thisServiceId))
+			if (!validServiceIdentifier(thisServiceId)) {
 				errs.addError({
 					code: "SL110",
 					message: `${thisServiceId.quote()} is not a valid service identifier`,
 					fragment: uID,
 					key: "invalid tag",
 				});
+				errs.errorDescription({ code: "SL110", description: "service identifier should be a tag: URI according to IETF RFC 4151" });
+			}
 			if (!uniqueServiceIdentifier(thisServiceId, knownServices))
 				errs.addError({
 					code: "SL111",
@@ -1995,7 +1991,7 @@ export default class ServiceListCheck {
 					type: WARNING,
 					code: "SL131",
 					key: "duplicate value",
-					message: `duplicate value (${TargetRegion.value}) specified for ${dvbi.e_TargetRegion.elementize()}`,
+					message: `duplicate value (${TargetRegion.text()}) specified for ${dvbi.e_TargetRegion.elementize()}`,
 					fragment: TargetRegion,
 				});
 			}
@@ -2309,7 +2305,7 @@ export default class ServiceListCheck {
 	 * @param {Class}  errs        Errors found in validaton
 	 * @param {String} log_prefix  the first part of the logging location (or null if no logging)
 	 */
-	/*public*/ doValidateServiceList(SLtext, errs, log_prefix=null) {
+	/*public*/ doValidateServiceList(SLtext, errs, log_prefix = null) {
 		this.#numRequests++;
 		if (!SLtext) {
 			errs.addError({
@@ -2682,13 +2678,20 @@ export default class ServiceListCheck {
 							key: "undefined region",
 						});
 					else {
-						if (foundRegion.selectable == false)
+						if (foundRegion.selectable == false) {
 							errs.addError({
 								code: "SL242",
 								message: `${dvbi.e_TargetRegion.elementize()} ${TargetRegion.text().quote()} in ${dvbi.e_LCNTable.elementize()} is not selectable`,
 								fragment: TargetRegion,
 								key: "unselectable region",
 							});
+							errs.errorDescription({
+								code: "SL242",
+								description: `the region ID specified in the ${dvbi.e_TargetRegion.elementize()} is defined with ${
+									dvbi.a_selectable
+								}=false in the ${dvbi.e_RegionList.elementize()} `,
+							});
+						}
 						foundRegion.used = true;
 					}
 
@@ -2821,7 +2824,7 @@ export default class ServiceListCheck {
 				errs.errorDescription({
 					code: "SL282",
 					clause: "see A177 table 14",
-					description: `lanugages used in ${tva.e_AudioAttributes.elementize()}${tva.e_AudioLanguage.elementize()} should be announced in ${dvbi.e_LanguageList.elementize()}`,
+					description: `only lanugages used in ${tva.e_AudioAttributes.elementize()}${tva.e_AudioLanguage.elementize()} should be announced in ${dvbi.e_LanguageList.elementize()}`,
 				});
 			}
 		});
diff --git a/utils.js b/utils.js
index 31e203f..142408a 100644
--- a/utils.js
+++ b/utils.js
@@ -1,6 +1,6 @@
 /**
  * utils.js
- * 
+ *
  * some usefule utility functions that may be used by more than one class
  */
 import { statSync, readFileSync } from "fs";
@@ -34,7 +34,7 @@ export function getElementByTagName(element, childElementName, index = null) {
 			if (!index) return getFirstElementByTagName(element, childElementName);
 
 			let cnt = 0;
-		  const ch1 = element.childNodes();
+			const ch1 = element.childNodes();
 			for (let i = 0; i < ch1.length; i++) {
 				if (ch1[i].type() == "element" && ch1[i].name() == childElementName) cnt++;
 				if (cnt >= index) return ch1[i];
@@ -200,3 +200,9 @@ export function DuplicatedValue(found, val) {
 	if (!f) found.push(val);
 	return f;
 }
+
+export function DumpString(str) {
+	let t = [];
+	for (let i = 0; i < str.length; i++) t.push(str.charCodeAt(i).toString(16));
+	return `"${str}" --> ${t.join(" ")}`;
+}