diff --git a/spec/locales-currencies-tz.html b/spec/locales-currencies-tz.html
index 5a72fac0..0ff175fa 100644
--- a/spec/locales-currencies-tz.html
+++ b/spec/locales-currencies-tz.html
@@ -40,17 +40,33 @@
Unicode Locale Extension Sequences
IsStructurallyValidLanguageTag ( _locale_ )
- The IsStructurallyValidLanguageTag abstract operation verifies that the _locale_ argument (which must be a String value)
+ The IsStructurallyValidLanguageTag abstract operation verifies that the _locale_ argument (which must be a String value) represents a well-formed "Unicode BCP 47 locale identifier", consistent with Unicode Technical Standard 35 section 3.2.
+
+
+
+ IsStructurallyValidLanguageTag returns *true* if all of the following conditions hold, *false* otherwise:
- - represents a well-formed "Unicode BCP 47 locale identifier" as specified in Unicode Technical Standard 35 section 3.2,
- - does not include duplicate variant subtags, and
- - does not include duplicate singleton subtags.
+ - _locale_ can be generated from the EBNF grammar in section 3.2 of the Unicode Technical Standard 35, starting with `unicode_locale_id`;
+ - _locale_ does not use any of the backwards compatiblity syntax described in Unicode Technical Standard #35 LDML ยง 3.3 BCP 47 Conformance; and
+ - interpreting _locale_ as `unicode_locale_id`,
+
+ - the `unicode_language_id` within _locale_ does not contain ASCII case-insensitively equivalent `unicode_variant_subtag` subtags, and
+ - if _locale_ contains an `extensions*` component, that component
+
+ - contains at most one `unicode_locale_extensions` component,
+ - contains at most one `transformed_extensions` component,
+ - does not contain multiple `other_extensions` components with ASCII case-insensitively equivalent `[alphanum-[tTuUxX]]` subtags, and
+ - if a `transformed_extensions` component is present and contains a `tlang` component, then the `(sep unicode_variant_subtag)*` within the `tlang` component does not contain ASCII case-insensitively equivalent `unicode_variant_subtag` subtags.
+
+
+
+
- The abstract operation returns true if _locale_ can be generated from the EBNF grammar in section 3.2 of the Unicode Technical Standard 35, starting with `unicode_locale_id`, and does not contain duplicate variant or singleton subtags (other than as a private use subtag). It returns false otherwise. Terminal value characters in the grammar are interpreted as the Unicode equivalents of the ASCII octet values given.
+ When evaluating each condition, terminal value characters in the grammar are interpreted as the corresponding ASCII code points.