diff --git a/icu4c/source/common/unicode/char16ptr.h b/icu4c/source/common/unicode/char16ptr.h
index 2fb8238f9a2..2b55cce6a9a 100644
--- a/icu4c/source/common/unicode/char16ptr.h
+++ b/icu4c/source/common/unicode/char16ptr.h
@@ -309,13 +309,19 @@ inline OldUChar *toOldUCharPtr(char16_t *p) {
 
 #ifndef U_FORCE_HIDE_INTERNAL_API
 /**
- * Is T convertible to a std::u16string_view or to a 16-bit std::wstring_view?
+ * Is T convertible to a std::u16string_view or some other 16-bit string view?
  * @internal
  */
 template<typename T>
 constexpr bool ConvertibleToU16StringView =
-    std::is_convertible_v<T, std::u16string_view> ||
-    (U_SIZEOF_WCHAR_T==2 && std::is_convertible_v<T, std::wstring_view>);
+    std::is_convertible_v<T, std::u16string_view>
+#if !U_CHAR16_IS_TYPEDEF
+    || std::is_convertible_v<T, std::basic_string_view<uint16_t>>
+#endif
+#if U_SIZEOF_WCHAR_T==2
+    || std::is_convertible_v<T, std::wstring_view>
+#endif
+    ;
 
 namespace internal {
 /**
@@ -324,6 +330,17 @@ namespace internal {
  */
 inline std::u16string_view toU16StringView(std::u16string_view sv) { return sv; }
 
+#if !U_CHAR16_IS_TYPEDEF
+/**
+ * Basically undefined behavior but sometimes necessary conversion
+ * from std::basic_string_view<uint16_t> to std::u16string_view.
+ * @internal
+ */
+inline std::u16string_view toU16StringView(std::basic_string_view<uint16_t> sv) {
+    return { ConstChar16Ptr(sv.data()), sv.length() };
+}
+#endif
+
 #if U_SIZEOF_WCHAR_T==2
 /**
  * Basically undefined behavior but sometimes necessary conversion
@@ -334,6 +351,29 @@ inline std::u16string_view toU16StringView(std::wstring_view sv) {
     return { ConstChar16Ptr(sv.data()), sv.length() };
 }
 #endif
+
+/**
+ * Pass-through overload.
+ * @internal
+ */
+template <typename T,
+          typename = typename std::enable_if_t<!std::is_pointer_v<std::remove_reference_t<T>>>>
+inline std::u16string_view toU16StringViewNullable(const T& text) {
+    return toU16StringView(text);
+}
+
+/**
+ * In case of nullptr, return an empty view.
+ * @internal
+ */
+template <typename T,
+          typename = typename std::enable_if_t<std::is_pointer_v<std::remove_reference_t<T>>>,
+          typename = void>
+inline std::u16string_view toU16StringViewNullable(const T& text) {
+    if (text == nullptr) return {};  // For backward compatibility.
+    return toU16StringView(text);
+}
+
 }  // internal
 #endif  // U_FORCE_HIDE_INTERNAL_API
 
diff --git a/icu4c/source/common/unicode/unistr.h b/icu4c/source/common/unicode/unistr.h
index 5f785fef942..72a2417694c 100644
--- a/icu4c/source/common/unicode/unistr.h
+++ b/icu4c/source/common/unicode/unistr.h
@@ -105,13 +105,11 @@ class UnicodeStringAppendable;  // unicode/appendable.h
  * this macro was provided for portability and efficiency when
  * initializing UnicodeStrings from literals.
  *
- * Since C++17 and ICU 76, you can use std::u16string_view literals with compile-time
+ * Since C++17 and ICU 76, you can use UTF-16 string literals with compile-time
  * length determination:
  * \code
- * #include &lt;string_view&gt;
- * using namespace std::string_view_literals;
- * UnicodeString str(u"literal"sv);
- * if (str == u"other literal"sv) { ... }
+ * UnicodeString str(u"literal");
+ * if (str == u"other literal") { ... }
  * \endcode
  *
  * The string parameter must be a C string literal.
@@ -335,13 +333,11 @@ public:
    * which is, or which is implicitly convertible to,
    * a std::u16string_view or (if U_SIZEOF_WCHAR_T==2) std::wstring_view.
    *
-   * For performance, you can use std::u16string_view literals with compile-time
+   * For performance, you can use UTF-16 string literals with compile-time
    * length determination:
    * \code
-   * #include &lt;string_view&gt;
-   * using namespace std::string_view_literals;
    * UnicodeString str = ...;
-   * if (str == u"literal"sv) { ... }
+   * if (str == u"literal") { ... }
    * \endcode
    * @param text The string view to compare to this string.
    * @return true if `text` contains the same characters as this one, false otherwise.
@@ -3104,6 +3100,7 @@ public:
    */
   UNISTR_FROM_CHAR_EXPLICIT UnicodeString(UChar32 ch);
 
+#ifdef U_HIDE_DRAFT_API
   /**
    * char16_t* constructor.
    *
@@ -3112,20 +3109,19 @@ public:
    * on the compiler command line or similar.
    *
    * Note, for string literals:
-   * Since C++17 and ICU 76, you can use std::u16string_view literals with compile-time
+   * Since C++17 and ICU 76, you can use UTF-16 string literals with compile-time
    * length determination:
    * \code
-   * #include &lt;string_view&gt;
-   * using namespace std::string_view_literals;
-   * UnicodeString str(u"literal"sv);
-   * if (str == u"other literal"sv) { ... }
+   * UnicodeString str(u"literal");
+   * if (str == u"other literal") { ... }
    * \endcode
    *
    * @param text The characters to place in the UnicodeString.  `text`
    * must be NUL (U+0000) terminated.
    * @stable ICU 2.0
    */
-  UNISTR_FROM_STRING_EXPLICIT UnicodeString(const char16_t *text);
+  UNISTR_FROM_STRING_EXPLICIT UnicodeString(const char16_t *text) :
+      UnicodeString(text, -1) {}
 
 #if !U_CHAR16_IS_TYPEDEF
   /**
@@ -3137,20 +3133,18 @@ public:
    * on the compiler command line or similar.
    *
    * Note, for string literals:
-   * Since C++17 and ICU 76, you can use std::u16string_view literals with compile-time
+   * Since C++17 and ICU 76, you can use UTF-16 string literals with compile-time
    * length determination:
    * \code
-   * #include &lt;string_view&gt;
-   * using namespace std::string_view_literals;
-   * UnicodeString str(u"literal"sv);
-   * if (str == u"other literal"sv) { ... }
+   * UnicodeString str(u"literal");
+   * if (str == u"other literal") { ... }
    * \endcode
    *
    * @param text NUL-terminated UTF-16 string
    * @stable ICU 59
    */
   UNISTR_FROM_STRING_EXPLICIT UnicodeString(const uint16_t *text) :
-      UnicodeString(ConstChar16Ptr(text)) {}
+      UnicodeString(ConstChar16Ptr(text), -1) {}
 #endif
 
 #if U_SIZEOF_WCHAR_T==2 || defined(U_IN_DOXYGEN)
@@ -3164,21 +3158,20 @@ public:
    * on the compiler command line or similar.
    *
    * Note, for string literals:
-   * Since C++17 and ICU 76, you can use std::u16string_view literals with compile-time
+   * Since C++17 and ICU 76, you can use UTF-16 string literals with compile-time
    * length determination:
    * \code
-   * #include &lt;string_view&gt;
-   * using namespace std::string_view_literals;
-   * UnicodeString str(u"literal"sv);
-   * if (str == u"other literal"sv) { ... }
+   * UnicodeString str(u"literal");
+   * if (str == u"other literal") { ... }
    * \endcode
    *
    * @param text NUL-terminated UTF-16 string
    * @stable ICU 59
    */
   UNISTR_FROM_STRING_EXPLICIT UnicodeString(const wchar_t *text) :
-      UnicodeString(ConstChar16Ptr(text)) {}
+      UnicodeString(ConstChar16Ptr(text), -1) {}
 #endif
+#endif  // U_HIDE_DRAFT_API
 
   /**
    * nullptr_t constructor.
@@ -3196,13 +3189,11 @@ public:
    * char16_t* constructor.
    *
    * Note, for string literals:
-   * Since C++17 and ICU 76, you can use std::u16string_view literals with compile-time
+   * Since C++17 and ICU 76, you can use UTF-16 string literals with compile-time
    * length determination:
    * \code
-   * #include &lt;string_view&gt;
-   * using namespace std::string_view_literals;
-   * UnicodeString str(u"literal"sv);
-   * if (str == u"other literal"sv) { ... }
+   * UnicodeString str(u"literal");
+   * if (str == u"other literal") { ... }
    * \endcode
    *
    * @param text The characters to place in the UnicodeString.
@@ -3219,13 +3210,11 @@ public:
    * Delegates to UnicodeString(const char16_t *, int32_t).
    *
    * Note, for string literals:
-   * Since C++17 and ICU 76, you can use std::u16string_view literals with compile-time
+   * Since C++17 and ICU 76, you can use UTF-16 string literals with compile-time
    * length determination:
    * \code
-   * #include &lt;string_view&gt;
-   * using namespace std::string_view_literals;
-   * UnicodeString str(u"literal"sv);
-   * if (str == u"other literal"sv) { ... }
+   * UnicodeString str(u"literal");
+   * if (str == u"other literal") { ... }
    * \endcode
    *
    * @param text UTF-16 string
@@ -3243,13 +3232,11 @@ public:
    * Delegates to UnicodeString(const char16_t *, int32_t).
    *
    * Note, for string literals:
-   * Since C++17 and ICU 76, you can use std::u16string_view literals with compile-time
+   * Since C++17 and ICU 76, you can use UTF-16 string literals with compile-time
    * length determination:
    * \code
-   * #include &lt;string_view&gt;
-   * using namespace std::string_view_literals;
-   * UnicodeString str(u"literal"sv);
-   * if (str == u"other literal"sv) { ... }
+   * UnicodeString str(u"literal");
+   * if (str == u"other literal") { ... }
    * \endcode
    *
    * @param text UTF-16 string
@@ -3283,9 +3270,9 @@ public:
    * @draft ICU 76
    */
   template<typename S, typename = std::enable_if_t<ConvertibleToU16StringView<S>>>
-  explicit inline UnicodeString(const S &text) {
+  UNISTR_FROM_STRING_EXPLICIT UnicodeString(const S &text) {
     fUnion.fFields.fLengthAndFlags = kShortString;
-    doAppend(internal::toU16StringView(text));
+    doAppend(internal::toU16StringViewNullable(text));
   }
 #endif  // U_HIDE_DRAFT_API
 
@@ -3304,13 +3291,11 @@ public:
    * so that both strings then alias the same readonly-text.
    *
    * Note, for string literals:
-   * Since C++17 and ICU 76, you can use std::u16string_view literals with compile-time
+   * Since C++17 and ICU 76, you can use UTF-16 string literals with compile-time
    * length determination:
    * \code
-   * #include &lt;string_view&gt;
-   * using namespace std::string_view_literals;
-   * UnicodeString alias = UnicodeString::readOnlyAlias(u"literal"sv);
-   * if (str == u"other literal"sv) { ... }
+   * UnicodeString alias = UnicodeString::readOnlyAlias(u"literal");
+   * if (str == u"other literal") { ... }
    * \endcode
    *
    * @param isTerminated specifies if `text` is `NUL`-terminated.
@@ -3393,13 +3378,11 @@ public:
    * the constructor that takes a US_INV (for its enum EInvariant).
    *
    * Note, for string literals:
-   * Since C++17 and ICU 76, you can use std::u16string_view literals with compile-time
+   * Since C++17 and ICU 76, you can use UTF-16 string literals with compile-time
    * length determination:
    * \code
-   * #include &lt;string_view&gt;
-   * using namespace std::string_view_literals;
-   * UnicodeString str(u"literal"sv);
-   * if (str == u"other literal"sv) { ... }
+   * UnicodeString str(u"literal");
+   * if (str == u"other literal") { ... }
    * \endcode
    *
    * It is recommended to mark this constructor "explicit" by
@@ -3509,13 +3492,11 @@ public:
    * \endcode
    *
    * Note, for string literals:
-   * Since C++17 and ICU 76, you can use std::u16string_view literals with compile-time
+   * Since C++17 and ICU 76, you can use UTF-16 string literals with compile-time
    * length determination:
    * \code
-   * #include &lt;string_view&gt;
-   * using namespace std::string_view_literals;
-   * UnicodeString str(u"literal"sv);
-   * if (str == u"other literal"sv) { ... }
+   * UnicodeString str(u"literal");
+   * if (str == u"other literal") { ... }
    * \endcode
    *
    * @param src String using only invariant characters.
diff --git a/icu4c/source/common/unistr.cpp b/icu4c/source/common/unistr.cpp
index 6389c85134f..ca577ecb156 100644
--- a/icu4c/source/common/unistr.cpp
+++ b/icu4c/source/common/unistr.cpp
@@ -230,11 +230,6 @@ UnicodeString::UnicodeString(UChar32 ch) {
   }
 }
 
-UnicodeString::UnicodeString(const char16_t *text) {
-  fUnion.fFields.fLengthAndFlags = kShortString;
-  doAppend(text, 0, -1);
-}
-
 UnicodeString::UnicodeString(const char16_t *text,
                              int32_t textLength) {
   fUnion.fFields.fLengthAndFlags = kShortString;