It sounds quite odd to me. But that doesn't seem to surprising if there is a mismatch between the languages and this is something of an amalgam rather than a systematic version of code-switching. I know that there is quite a bit of research that shows code-switching is structured grammatically and even that the switches tend to occur at phrase boundaries (and sometimes predictably in certain domains), but I don't know to whether (or to what extent) there is freer, less systematic code-switching, or if not how common speech errors are.
The idea of blending the two surface structures in an amalgam is interesting to me. I've been doing some research about that sort of mixed surface structure that doesn't really fit more general grammatical properties of a language, but only from a monolingual perspective, not about borrowed constructions which adds a whole new layer to it. If you do end up finding some way along those lines to explain this or especially if you find that this happens often and results in new mixed expression types (as opposed to one-time errors), please post back with more information. (If you happen to be interested in the research I mentioned you can see some slides here:
http://publish.illinois.edu/djross3/files/2018/02/GrammaticalAnomalies.pdf -- I'll also have a proceedings paper for that available soon, let me know if you want it. But of course that has nothing to do with code-switching, so it would only relate if you think something similar is going on.)
--
On the other hand, maybe it's not the structure but the semantics that doesn't really make sense to me. If I'm parsing that correctly it says "my terribly most beautiful baby", and I don't understand how a superlative (or comparative?) can be "terribly". "My very most beautiful baby" sounds odd, unless the comparison is to the speaker's other children! But I guess it's just a way to be extremely emphatic. So in that sense, if interpreted as if it makes semantic sense, maybe the grammatical structure works. But my initial reaction (as in my comment above) was to assume a different parse because I didn't really understand that meaning. So we'd have to check with the speaker about what they really mean there...
