diff --git a/make/doc-i18n-root-rules.make b/make/doc-i18n-root-rules.make
index f510ded..83f2ee6 100644
--- a/make/doc-i18n-root-rules.make
+++ b/make/doc-i18n-root-rules.make
@@ -18,7 +18,7 @@ $(top-build-dir)/Documentation/$(outdir)/%.$(ISOLANG).html: $(outdir)/%.texi $(X
 
 $(top-build-dir)/Documentation/$(outdir)/%.$(ISOLANG).pdf: $(outdir)/%.texi
 	cd $(outdir) && \
-	    texi2pdf $(TEXI2PDF_FLAGS) $(TEXINFO_PAPERSIZE_OPTION) $*.texi && \
+	    LC_ALL=C texi2pdf $(TEXI2PDF_FLAGS) $(TEXINFO_PAPERSIZE_OPTION) $*.texi && \
 	    mkdir -p $(dir $@) && mv $*.pdf $@
 
 $(outdir)/version.%: $(top-src-dir)/VERSION