diff --git a/sphinx/builders/latex/__init__.py b/sphinx/builders/latex/__init__.py
index 354b20284..4a7ec5e31 100644
--- a/sphinx/builders/latex/__init__.py
+++ b/sphinx/builders/latex/__init__.py
@@ -20,7 +20,7 @@ import sphinx.builders.latex.nodes  # NOQA  # Workaround: import this before wri
 from sphinx import package_dir, addnodes, highlighting
 from sphinx.application import Sphinx
 from sphinx.builders import Builder
-from sphinx.builders.latex.constants import ADDITIONAL_SETTINGS, DEFAULT_SETTINGS
+from sphinx.builders.latex.constants import ADDITIONAL_SETTINGS, DEFAULT_SETTINGS, SHORTHANDOFF
 from sphinx.builders.latex.theming import Theme, ThemeFactory
 from sphinx.builders.latex.util import ExtBabel
 from sphinx.config import Config, ENUM
@@ -133,6 +133,7 @@ class LaTeXBuilder(Builder):
 
         self.init_context()
         self.init_babel()
+        self.init_multilingual()
 
     def get_outdated_docs(self) -> Union[str, List[str]]:
         return 'all documents'  # for now
@@ -208,6 +209,41 @@ class LaTeXBuilder(Builder):
             logger.warning(__('no Babel option known for language %r'),
                            self.config.language)
 
+    def init_multilingual(self) -> None:
+        if self.context['latex_engine'] == 'pdflatex':
+            if not self.babel.uses_cyrillic():
+                if 'X2' in self.context['fontenc']:
+                    self.context['substitutefont'] = '\\usepackage{substitutefont}'
+                    self.context['textcyrillic'] = '\\usepackage[Xtwo]{sphinxcyrillic}'
+                elif 'T2A' in self.context['fontenc']:
+                    self.context['substitutefont'] = '\\usepackage{substitutefont}'
+                    self.context['textcyrillic'] = '\\usepackage[TtwoA]{sphinxcyrillic}'
+            if 'LGR' in self.context['fontenc']:
+                self.context['substitutefont'] = '\\usepackage{substitutefont}'
+            else:
+                self.context['textgreek'] = ''
+
+        # 'babel' key is public and user setting must be obeyed
+        if self.context['babel']:
+            self.context['classoptions'] += ',' + self.babel.get_language()
+            # this branch is not taken for xelatex/lualatex if default settings
+            self.context['multilingual'] = self.context['babel']
+            if self.config.language:
+                self.context['shorthandoff'] = SHORTHANDOFF
+
+                # Times fonts don't work with Cyrillic languages
+                if self.babel.uses_cyrillic() and 'fontpkg' not in self.config.latex_elements:
+                    self.context['fontpkg'] = ''
+        elif self.context['polyglossia']:
+            self.context['classoptions'] += ',' + self.babel.get_language()
+            options = self.babel.get_mainlanguage_options()
+            if options:
+                language = r'\setmainlanguage[%s]{%s}' % (options, self.babel.get_language())
+            else:
+                language = r'\setmainlanguage{%s}' % self.babel.get_language()
+
+            self.context['multilingual'] = '%s\n%s' % (self.context['polyglossia'], language)
+
     def write_stylesheet(self) -> None:
         highlighter = highlighting.PygmentsBridge('latex', self.config.pygments_style)
         stylesheet = path.join(self.outdir, 'sphinxhighlight.sty')
diff --git a/sphinx/builders/latex/constants.py b/sphinx/builders/latex/constants.py
index 70fd0b1d1..9a89036bf 100644
--- a/sphinx/builders/latex/constants.py
+++ b/sphinx/builders/latex/constants.py
@@ -192,3 +192,11 @@ ADDITIONAL_SETTINGS = {
         'fontpkg':      XELATEX_GREEK_DEFAULT_FONTPKG,
     },
 }  # type: Dict[Any, Dict[str, Any]]
+
+
+SHORTHANDOFF = r'''
+\ifdefined\shorthandoff
+  \ifnum\catcode`\=\string=\active\shorthandoff{=}\fi
+  \ifnum\catcode`\"=\active\shorthandoff{"}\fi
+\fi
+'''
diff --git a/sphinx/writers/latex.py b/sphinx/writers/latex.py
index cfce52f7f..9390ba5de 100644
--- a/sphinx/writers/latex.py
+++ b/sphinx/writers/latex.py
@@ -50,13 +50,6 @@ if False:
 
 logger = logging.getLogger(__name__)
 
-SHORTHANDOFF = r'''
-\ifdefined\shorthandoff
-  \ifnum\catcode`\=\string=\active\shorthandoff{=}\fi
-  \ifnum\catcode`\"=\active\shorthandoff{"}\fi
-\fi
-'''
-
 MAX_CITATION_LABEL_LENGTH = 8
 LATEXSECTIONNAMES = ["part", "chapter", "section", "subsection",
                      "subsubsection", "paragraph", "subparagraph"]
@@ -395,44 +388,6 @@ class LaTeXTranslator(SphinxTranslator):
             logger.warning(__('no Babel option known for language %r'),
                            self.config.language)
 
-        # set up multilingual module...
-        if self.elements['latex_engine'] == 'pdflatex':
-            if not self.babel.uses_cyrillic():
-                if 'X2' in self.elements['fontenc']:
-                    self.elements['substitutefont'] = '\\usepackage{substitutefont}'
-                    self.elements['textcyrillic'] = ('\\usepackage[Xtwo]'
-                                                     '{sphinxcyrillic}')
-                elif 'T2A' in self.elements['fontenc']:
-                    self.elements['substitutefont'] = '\\usepackage{substitutefont}'
-                    self.elements['textcyrillic'] = ('\\usepackage[TtwoA]'
-                                                     '{sphinxcyrillic}')
-            if 'LGR' in self.elements['fontenc']:
-                self.elements['substitutefont'] = '\\usepackage{substitutefont}'
-            else:
-                self.elements['textgreek'] = ''
-        # 'babel' key is public and user setting must be obeyed
-        if self.elements['babel']:
-            self.elements['classoptions'] += ',' + self.babel.get_language()
-            # this branch is not taken for xelatex/lualatex if default settings
-            self.elements['multilingual'] = self.elements['babel']
-            if self.config.language:
-                self.elements['shorthandoff'] = SHORTHANDOFF
-
-                # Times fonts don't work with Cyrillic languages
-                if self.babel.uses_cyrillic() and 'fontpkg' not in self.config.latex_elements:
-                    self.elements['fontpkg'] = ''
-        elif self.elements['polyglossia']:
-            self.elements['classoptions'] += ',' + self.babel.get_language()
-            options = self.babel.get_mainlanguage_options()
-            if options:
-                mainlanguage = r'\setmainlanguage[%s]{%s}' % (options,
-                                                              self.babel.get_language())
-            else:
-                mainlanguage = r'\setmainlanguage{%s}' % self.babel.get_language()
-
-            self.elements['multilingual'] = '%s\n%s' % (self.elements['polyglossia'],
-                                                        mainlanguage)
-
         minsecnumdepth = self.secnumdepth  # 2 from legacy sphinx manual/howto
         if self.document.get('tocdepth'):
             # reduce tocdepth if `part` or `chapter` is used for top_sectionlevel
@@ -2177,6 +2132,7 @@ deprecated_alias('sphinx.writers.latex',
                      'DEFAULT_SETTINGS': constants.DEFAULT_SETTINGS,
                      'LUALATEX_DEFAULT_FONTPKG': constants.LUALATEX_DEFAULT_FONTPKG,
                      'PDFLATEX_DEFAULT_FONTPKG': constants.PDFLATEX_DEFAULT_FONTPKG,
+                     'SHORTHANDOFF': constants.SHORTHANDOFF,
                      'XELATEX_DEFAULT_FONTPKG': constants.XELATEX_DEFAULT_FONTPKG,
                      'XELATEX_GREEK_DEFAULT_FONTPKG': constants.XELATEX_GREEK_DEFAULT_FONTPKG,
                      'ExtBabel': ExtBabel,
diff --git a/tests/test_build_latex.py b/tests/test_build_latex.py
index d55a3b895..61020b861 100644
--- a/tests/test_build_latex.py
+++ b/tests/test_build_latex.py
@@ -99,7 +99,7 @@ def skip_if_stylefiles_notfound(testfunc):
 def test_build_latex_doc(app, status, warning, engine, docclass):
     app.config.latex_engine = engine
     app.config.latex_documents = [app.config.latex_documents[0][:4] + (docclass,)]
-    app.builder.init_context()
+    app.builder.init()
 
     LaTeXTranslator.ignore_missing_images = True
     app.builder.build_all()