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                                           939
SECTION 10.8                                                         Accessibility Support



Example 10.19
  2 0 obj                                % Page object
     << /Type /Page
        /Contents 3 0 R                  % Content stream
        …
     >>
  endobj
  3 0 obj                                   % Page's content stream
      << /Length … >>
  stream
      BT
         ( See you later, or as Arnold would say, ) Tj
         /Span << /Lang ( es-MX ) >>        % Start of marked-content sequence
             BDC
                ( Hasta la vista . ) Tj
             EMC                            % End of marked-content sequence
      ET
  endstream
  endobj

Where logical structure is described (by a structure hierarchy) within a docu-
ment, the Lang entry in the document catalog sets the default for the document.
Below that, any language specifications within the structure hierarchy apply in
this order:
• A structure element’s language specification
  Note: If a structure element does not have a Lang entry, the element inherits its
  language from any parent element that has one.
• Within a structure element, a language specification for a nested structure ele-
  ment or marked-content sequence

In Example 10.20, the Lang entry in the structure element dictionary (specifying
English) applies to the marked-content sequence having an MCID (marked-
content identifier) value of 0 within the indicated page’s content stream. However,
nested within that marked-content sequence is another one in which the Lang
property attached with the Span tag (specifying Spanish) overrides the structure
element’s language specification.

Note: This example and the next one below omit required StructParents entries in
the objects used as content items (see “Finding Structure Elements from Content
Items” on page 868).

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