Code-switching (within a sentence) between a Conlang and a Natlang or other Conlang.

Hello, the list.
I am reading a book on Tree-Adjoining Grammars, among others.
It has one chapter on code-switching.

I wonder, has anyone tried to develop rules and/or examples for their
conlang codeswitching with a familiar natlang, or with another conlang
(whether their own or someone else's)?

-----

This chapter is about how neither Lexicalized TAGs nor just plain TAGs can
handle certain aspects of code-switching.

If a sentence is partly in one language and partly in another, then "head
and dependent(s)" phrases have their word-order etc. governed by the rule
that applies to the language the "head" comes from.

But say the two languages are, one of them, prepositional, and the other is
postpositional.  Then the prepositons will always come first even if their
objects are from postpositional languages, and the postpositions will
always come last even if their objects are from prepositional languages.

But, if the phrase is not a "head-and-complement" type phrase, their is no
such rule.

As examples, they say, certain adjectives (e.g. "mere") act as head-words,
with the modified noun-phrase as a dependent.  These adjectives can't be
used as predicate attributives (*the fact is mere); they can't be used with
indefinite nouns (*the mere one); and the equivalent adjective in two
different languages tend to have the same word-order relative to the
modified noun, even if most adjectives in one of the languages tend to come
in the other order.

The "complements are distributed according to the language of the head"
rule applies to adjectives such as "mere".

However, other adjectives (like "red") don't act as heads.  And, with these
adjectives, the distribution is not predictable.
If the sentence is in a mixture of an A-N language and an N-A language, all
four orders are possible;
Adjective from A-N, noun from N-A, order "A N";
Adjective from A-N, noun from N-A, order "N A";
Adjective from N-A, noun from A-N, order "A N";
Adjective from N-A, noun from A-N, order "N A".
Indeed, if most of the sentence is in an A-N language, but both the
adjective and the noun are from an N-A language, both "A N" and "N A"
orders are possible; likewise if most of the sentence is in an N-A
language, but the adjective and noun are both from an A-N language, both "N
A" and "A N" are possible.

---

Tom H.C. in MI