setLanguageTag(vLanguageTag) {
			const oLanguageTag = createLanguageTag(vLanguageTag);
			check(vLanguageTag == null || oLanguageTag, "vLanguageTag must be a BCP47 language tag or Java Locale id or null");
			const oOldLanguageTag = Formatting.getLanguageTag();
			oWritableConfig.set("sapUiFormatLocale", oLanguageTag?.toString());
			const oCurrentLanguageTag = Formatting.getLanguageTag();
			if (oOldLanguageTag.toString() !== oCurrentLanguageTag.toString()) {
				const bFireEvent = !mChanges;
				mChanges ??= {};
				mChanges.languageTag = oCurrentLanguageTag.toString();
				if (bFireEvent) {
					fireChange();
				}
			}
		}
Sets a new language tag to be used from now on for retrieving language
specific formatters. Modifying this setting does not have an impact on
the retrieval of translated texts!

Can either be set to a concrete value (a BCP47 or Java locale compliant
language tag) or to <code>null</code>. When set to <code>null</code> (default
value) then locale specific formatters are retrieved for the current language.

After changing the format locale, the framework tries to update localization
specific parts of the UI. See the documentation of
{@link module:sap/base/i18n/Localization.setLanguage Localization.setLanguage()}
for details and restrictions.

<b>Note</b>: When a language tag is set, it has higher priority than a number,
date or time format defined with a call to <code>setABAPNumberFormat</code>,
<code>setABAPDateFormat</code> or <code>setABAPTimeFormat</code>.

<b>Note</b>: See documentation of
{@link module:sap/base/i18n/Localization.setLanguage Localization.setLanguage()}
for restrictions.

@param {string|module:sap/base/i18n/LanguageTag|null} vLanguageTag the new BCP47 compliant language tag;
  case doesn't matter and underscores can be used instead of dashes to separate
  components (compatibility with Java Locale IDs)
@throws {TypeError} When <code>sLanguageTag</code> is given, but is not a valid BCP47 language
  tag or Java locale identifier
@public
@since 1.120