diff --git a/lib/doc/translation.html b/lib/doc/translation.html
index bbd2764a5..c9c744401 100644
--- a/lib/doc/translation.html
+++ b/lib/doc/translation.html
@@ -224,6 +224,29 @@ Here is a description of each of the modules:
 <LI><B>RGLCategories</B> stands for the type system of the standard RGL, the module named <CODE>Cat</CODE>.
 </UL>
 
+<P>
+A guiding principle is thus that the translation grammar preserves <I>as much as possible</I> of the RGL, so that
+duplicated work is avoided. But as the purposes of the two are different, not everything is possible. Two 
+diverging principles have already been mentioned:
+</P>
+
+<UL>
+<LI><B>Free variation</B>. The RGL bans free variation, because library users need to have full control on selecting
+  variants. For instance, English negation has two forms, contracted (<I>don't</I>) and uncontracted (<I>do not</I>),
+  which in the translation grammar are treated as variants. But RGL users sometimes need to choose the one or the
+  other, for instance, excluding contracted negation in formal style.
+<P></P>
+<LI><B>Semantic distinctions</B>. The RGL avoids semantic distinctions that are not absolutely necessary for syntax.
+  The reason for this is the ambition to keep the library as simple as possible, in particular for the voluntary
+  implementors of new languages. But meaning-preserving translation needs more distinctions, for instance, in
+  word senses, subcategorizations, selection restrictions, and tense and aspect systems.
+</UL>
+
+<P>
+The old design principles of the RGL are thus kept in force, and this is made possible by separating parts of the
+translation grammar modules from the RGL. 
+</P>
+
 <!-- html code generated by txt2tags 2.6 (http://txt2tags.org) -->
 <!-- cmdline: txt2tags -thtml translation.txt -->
 </BODY></HTML>
diff --git a/lib/doc/translation.txt b/lib/doc/translation.txt
index f8e626537..3d5281a81 100644
--- a/lib/doc/translation.txt
+++ b/lib/doc/translation.txt
@@ -193,4 +193,28 @@ Here is a description of each of the modules:
 
 
 
+A guiding principle is thus that the translation grammar preserves //as much as possible// of the RGL, so that
+duplicated work is avoided. But as the purposes of the two are different, not everything is possible. Two 
+diverging principles have already been mentioned:
+
+- **Free variation**. The RGL bans free variation, because library users need to have full control on selecting
+  variants. For instance, English negation has two forms, contracted (//don't//) and uncontracted (//do not//),
+  which in the translation grammar are treated as variants. But RGL users sometimes need to choose the one or the
+  other, for instance, excluding contracted negation in formal style.
+
+- **Semantic distinctions**. The RGL avoids semantic distinctions that are not absolutely necessary for syntax.
+  The reason for this is the ambition to keep the library as simple as possible, in particular for the voluntary
+  implementors of new languages. But meaning-preserving translation needs more distinctions, for instance, in
+  word senses, subcategorizations, selection restrictions, and tense and aspect systems.
+
+
+The old design principles of the RGL are thus kept in force, and this is made possible by separating parts of the
+translation grammar modules from the RGL. 
+
+
+
+
+
+
+